---
_id: '12964'
abstract:
- lang: eng
text: "Pattern formation is of great importance for its contribution across different
biological behaviours. During developmental processes for example, patterns of
chemical gradients are\r\nestablished to determine cell fate and complex tissue
patterns emerge to define structures such\r\nas limbs and vascular networks. Patterns
are also seen in collectively migrating groups, for\r\ninstance traveling waves
of density emerging in moving animal flocks as well as collectively migrating
cells and tissues. To what extent these biological patterns arise spontaneously
through\r\nthe local interaction of individual constituents or are dictated by
higher level instructions is\r\nstill an open question however there is evidence
for the involvement of both types of process.\r\nWhere patterns arise spontaneously
there is a long standing interest in how far the interplay\r\nof mechanics, e.g.
force generation and deformation, and chemistry, e.g. gene regulation\r\nand signaling,
contributes to the behaviour. This is because many systems are able to both\r\nchemically
regulate mechanical force production and chemically sense mechanical deformation,\r\nforming
mechano-chemical feedback loops which can potentially become unstable towards\r\nspatio
and/or temporal patterning.\r\nWe work with experimental collaborators to investigate
the possibility that this type of\r\ninteraction drives pattern formation in biological
systems at different scales. We focus first on\r\ntissue-level ERK-density waves
observed during the wound healing response across different\r\nsystems where many
previous studies have proposed that patterns depend on polarized cell\r\nmigration
and arise from a mechanical flocking-like mechanism. By combining theory with\r\nmechanical
and optogenetic perturbation experiments on in vitro monolayers we instead find\r\nevidence
for mechanochemical pattern formation involving only scalar bilateral feedbacks\r\nbetween
ERK signaling and cell contraction. We perform further modeling and experiment\r\nto
study how this instability couples with polar cell migration in order to produce
a robust\r\nand efficient wound healing response. In a following chapter we implement
ERK-density\r\ncoupling and cell migration in a 2D active vertex model to investigate
the interaction of\r\nERK-density patterning with different tissue rheologies
and find that the spatio-temporal\r\ndynamics are able to both locally and globally
fluidize a tissue across the solid-fluid glass\r\ntransition. In a last chapter
we move towards lower spatial scales in the context of subcellular\r\npatterning
of the cell cytoskeleton where we investigate the transition between phases of\r\nspatially
homogeneous temporal oscillations and chaotic spatio-temporal patterning in the\r\ndynamics
of myosin and ROCK activities (a motor component of the actomyosin cytoskeleton\r\nand
its activator). Experimental evidence supports an intrinsic chemical oscillator
which we\r\nencode in a reaction model and couple to a contractile active gel
description of the cell cortex.\r\nThe model exhibits phases of chemical oscillations
and contractile spatial patterning which\r\nreproduce many features of the dynamics
seen in Drosophila oocyte epithelia in vivo. However,\r\nadditional pharmacological
perturbations to inhibit myosin contractility leaves the role of\r\ncontractile
instability unclear. We discuss alternative hypotheses and investigate the possibility\r\nof
reaction-diffusion instability."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Daniel R
full_name: Boocock, Daniel R
id: 453AF628-F248-11E8-B48F-1D18A9856A87
last_name: Boocock
orcid: 0000-0002-1585-2631
citation:
ama: Boocock DR. Mechanochemical pattern formation across biological scales. 2023.
doi:10.15479/at:ista:12964
apa: Boocock, D. R. (2023). Mechanochemical pattern formation across biological
scales. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:12964
chicago: Boocock, Daniel R. “Mechanochemical Pattern Formation across Biological
Scales.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:12964.
ieee: D. R. Boocock, “Mechanochemical pattern formation across biological scales,”
Institute of Science and Technology Austria, 2023.
ista: Boocock DR. 2023. Mechanochemical pattern formation across biological scales.
Institute of Science and Technology Austria.
mla: Boocock, Daniel R. Mechanochemical Pattern Formation across Biological Scales.
Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:12964.
short: D.R. Boocock, Mechanochemical Pattern Formation across Biological Scales,
Institute of Science and Technology Austria, 2023.
date_created: 2023-05-15T14:52:36Z
date_published: 2023-05-17T00:00:00Z
date_updated: 2023-08-04T11:02:40Z
day: '17'
ddc:
- '530'
degree_awarded: PhD
department:
- _id: GradSch
- _id: EdHa
doi: 10.15479/at:ista:12964
ec_funded: 1
file:
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creator: dboocock
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date_updated: 2023-05-17T14:35:13Z
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relation: source_file
file_date_updated: 2023-05-19T07:04:25Z
has_accepted_license: '1'
language:
- iso: eng
license: https://creativecommons.org/licenses/by-nc-sa/4.0/
month: '05'
oa_version: Published Version
page: '146'
project:
- _id: 2564DBCA-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '665385'
name: International IST Doctoral Program
publication_identifier:
isbn:
- 978-3-99078-032-9
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '8602'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Edouard B
full_name: Hannezo, Edouard B
id: 3A9DB764-F248-11E8-B48F-1D18A9856A87
last_name: Hannezo
orcid: 0000-0001-6005-1561
title: Mechanochemical pattern formation across biological scales
tmp:
image: /images/cc_by_nc_sa.png
legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
BY-NC-SA 4.0)
short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '12885'
abstract:
- lang: eng
text: 'High-performance semiconductors rely upon precise control of heat and charge
transport. This can be achieved by precisely engineering defects in polycrystalline
solids. There are multiple approaches to preparing such polycrystalline semiconductors,
and the transformation of solution-processed colloidal nanoparticles is appealing
because colloidal nanoparticles combine low cost with structural and compositional
tunability along with rich surface chemistry. However, the multiple processes
from nanoparticle synthesis to the final bulk nanocomposites are very complex.
They involve nanoparticle purification, post-synthetic modifications, and finally
consolidation (thermal treatments and densification). All these properties dictate
the final material’s composition and microstructure, ultimately affecting its
functional properties. This thesis explores the synthesis, surface chemistry and
consolidation of colloidal semiconductor nanoparticles into dense solids. In particular,
the transformations that take place during these processes, and their effect on
the material’s transport properties are evaluated. '
acknowledged_ssus:
- _id: EM-Fac
- _id: NanoFab
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Mariano
full_name: Calcabrini, Mariano
id: 45D7531A-F248-11E8-B48F-1D18A9856A87
last_name: Calcabrini
orcid: 0000-0003-4566-5877
citation:
ama: 'Calcabrini M. Nanoparticle-based semiconductor solids: From synthesis to consolidation.
2023. doi:10.15479/at:ista:12885'
apa: 'Calcabrini, M. (2023). Nanoparticle-based semiconductor solids: From synthesis
to consolidation. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:12885'
chicago: 'Calcabrini, Mariano. “Nanoparticle-Based Semiconductor Solids: From Synthesis
to Consolidation.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:12885.'
ieee: 'M. Calcabrini, “Nanoparticle-based semiconductor solids: From synthesis to
consolidation,” Institute of Science and Technology Austria, 2023.'
ista: 'Calcabrini M. 2023. Nanoparticle-based semiconductor solids: From synthesis
to consolidation. Institute of Science and Technology Austria.'
mla: 'Calcabrini, Mariano. Nanoparticle-Based Semiconductor Solids: From Synthesis
to Consolidation. Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:12885.'
short: 'M. Calcabrini, Nanoparticle-Based Semiconductor Solids: From Synthesis to
Consolidation, Institute of Science and Technology Austria, 2023.'
date_created: 2023-05-02T07:58:57Z
date_published: 2023-04-28T00:00:00Z
date_updated: 2023-08-14T07:25:26Z
day: '28'
ddc:
- '546'
- '541'
degree_awarded: PhD
department:
- _id: GradSch
- _id: MaIb
doi: 10.15479/at:ista:12885
ec_funded: 1
file:
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file_size: 99627036
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date_updated: 2023-05-02T07:42:45Z
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file_date_updated: 2023-05-02T07:43:18Z
has_accepted_license: '1'
language:
- iso: eng
month: '04'
oa: 1
oa_version: Published Version
page: '82'
project:
- _id: 2564DBCA-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '665385'
name: International IST Doctoral Program
publication_identifier:
isbn:
- 978-3-99078-028-2
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '10806'
relation: part_of_dissertation
status: public
- id: '10042'
relation: part_of_dissertation
status: public
- id: '12237'
relation: part_of_dissertation
status: public
- id: '9118'
relation: part_of_dissertation
status: public
- id: '10123'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Maria
full_name: Ibáñez, Maria
id: 43C61214-F248-11E8-B48F-1D18A9856A87
last_name: Ibáñez
orcid: 0000-0001-5013-2843
title: 'Nanoparticle-based semiconductor solids: From synthesis to consolidation'
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '12891'
abstract:
- lang: eng
text: "The tight spatiotemporal coordination of signaling activity determining embryo\r\npatterning
and the physical processes driving embryo morphogenesis renders\r\nembryonic development
robust, such that key developmental processes can unfold\r\nrelatively normally
even outside of the full embryonic context. For instance, embryonic\r\nstem cell
cultures can recapitulate the hallmarks of gastrulation, i.e. break symmetry\r\nleading
to germ layer formation and morphogenesis, in a very reduced environment.\r\nThis
leads to questions on specific contributions of embryo-specific features, such
as\r\nthe presence of extraembryonic tissues, which are inherently involved in
gastrulation\r\nin the full embryonic context. To address this, we established
zebrafish embryonic\r\nexplants without the extraembryonic yolk cell, an important
player as a signaling\r\nsource and for morphogenesis during gastrulation, as
a model of ex vivo development.\r\nWe found that dorsal-marginal determinants
are required and sufficient in these\r\nexplants to form and pattern all three
germ layers. However, formation of tissues,\r\nwhich require the highest Nodal-signaling
levels, is variable, demonstrating a\r\ncontribution of extraembryonic tissues
for reaching peak Nodal signaling levels.\r\nBlastoderm explants also undergo
gastrulation-like axis elongation. We found that this\r\nelongation movement shows
hallmarks of oriented mesendoderm cell intercalations\r\ntypically associated
with dorsal tissues in the intact embryo. These are disrupted by\r\nuniform upregulation
of BMP signaling activity and concomitant explant ventralization,\r\nsuggesting
that tight spatial control of BMP signaling is a prerequisite for explant\r\nmorphogenesis.
This control is achieved by Nodal signaling, which is critical for\r\neffectively
downregulating BMP signaling in the mesendoderm, highlighting that Nodal\r\nsignaling
is not only directly required for mesendoderm cell fate specification and\r\nmorphogenesis,
but also by maintaining low levels of BMP signaling at the dorsal side.\r\nCollectively,
we provide insights into the capacity and organization of signaling and\r\nmorphogenetic
domains to recapitulate features of zebrafish gastrulation outside of\r\nthe full
embryonic context."
acknowledged_ssus:
- _id: Bio
- _id: LifeSc
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Alexandra
full_name: Schauer, Alexandra
id: 30A536BA-F248-11E8-B48F-1D18A9856A87
last_name: Schauer
orcid: 0000-0001-7659-9142
citation:
ama: 'Schauer A. Mesendoderm formation in zebrafish gastrulation: The role of extraembryonic
tissues. 2023. doi:10.15479/at:ista:12891'
apa: 'Schauer, A. (2023). Mesendoderm formation in zebrafish gastrulation: The
role of extraembryonic tissues. Institute of Science and Technology Austria.
https://doi.org/10.15479/at:ista:12891'
chicago: 'Schauer, Alexandra. “Mesendoderm Formation in Zebrafish Gastrulation:
The Role of Extraembryonic Tissues.” Institute of Science and Technology Austria,
2023. https://doi.org/10.15479/at:ista:12891.'
ieee: 'A. Schauer, “Mesendoderm formation in zebrafish gastrulation: The role of
extraembryonic tissues,” Institute of Science and Technology Austria, 2023.'
ista: 'Schauer A. 2023. Mesendoderm formation in zebrafish gastrulation: The role
of extraembryonic tissues. Institute of Science and Technology Austria.'
mla: 'Schauer, Alexandra. Mesendoderm Formation in Zebrafish Gastrulation: The
Role of Extraembryonic Tissues. Institute of Science and Technology Austria,
2023, doi:10.15479/at:ista:12891.'
short: 'A. Schauer, Mesendoderm Formation in Zebrafish Gastrulation: The Role of
Extraembryonic Tissues, Institute of Science and Technology Austria, 2023.'
date_created: 2023-05-05T08:48:20Z
date_published: 2023-05-05T00:00:00Z
date_updated: 2023-08-21T06:25:48Z
day: '05'
ddc:
- '570'
degree_awarded: PhD
department:
- _id: GradSch
- _id: CaHe
doi: 10.15479/at:ista:12891
ec_funded: 1
file:
- access_level: closed
checksum: 59b0303dc483f40a96a610a90aab7ee9
content_type: application/pdf
creator: aschauer
date_created: 2023-05-05T13:01:14Z
date_updated: 2023-05-05T13:01:14Z
embargo: 2024-05-05
embargo_to: open_access
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file_name: Thesis_Schauer_final.pdf
file_size: 31434230
relation: main_file
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creator: aschauer
date_created: 2023-05-05T13:04:15Z
date_updated: 2023-05-05T13:04:15Z
file_id: '12908'
file_name: Thesis_Schauer_final.docx
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relation: source_file
file_date_updated: 2023-05-05T13:04:15Z
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language:
- iso: eng
month: '05'
oa_version: Published Version
page: '190'
project:
- _id: 260F1432-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '742573'
name: Interaction and feedback between cell mechanics and fate specification in
vertebrate gastrulation
- _id: 26B1E39C-B435-11E9-9278-68D0E5697425
grant_number: '25239'
name: 'Mesendoderm specification in zebrafish: The role of extraembryonic tissues'
publication_identifier:
issn:
- 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '8966'
relation: part_of_dissertation
status: public
- id: '7888'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Carl-Philipp J
full_name: Heisenberg, Carl-Philipp J
id: 39427864-F248-11E8-B48F-1D18A9856A87
last_name: Heisenberg
orcid: 0000-0002-0912-4566
title: 'Mesendoderm formation in zebrafish gastrulation: The role of extraembryonic
tissues'
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '13175'
abstract:
- lang: eng
text: "About a 100 years ago, we discovered that our universe is inherently noisy,
that is, measuring any physical quantity with a precision beyond a certain point
is not possible because of an omnipresent inherent noise. We call this - the quantum
noise. Certain physical processes allow this quantum noise to get correlated in
conjugate physical variables. These quantum correlations can be used to go beyond
the potential of our inherently noisy universe and obtain a quantum advantage
over the classical applications. \r\n\r\nQuantum noise being inherent also means
that, at the fundamental level, the physical quantities are not well defined and
therefore, objects can stay in multiple states at the same time. For example,
the position of a particle not being well defined means that the particle is in
multiple positions at the same time. About 4 decades ago, we started exploring
the possibility of using objects which can be in multiple states at the same time
to increase the dimensionality in computation. Thus, the field of quantum computing
was born. We discovered that using quantum entanglement, a property closely related
to quantum correlations, can be used to speed up computation of certain problems,
such as factorisation of large numbers, faster than any known classical algorithm.
Thus began the pursuit to make quantum computers a reality. \r\n\r\nTill date,
we have explored quantum control over many physical systems including photons,
spins, atoms, ions and even simple circuits made up of superconducting material.
However, there persists one ubiquitous theme. The more readily a system interacts
with an external field or matter, the more easily we can control it. But this
also means that such a system can easily interact with a noisy environment and
quickly lose its coherence. Consequently, such systems like electron spins need
to be protected from the environment to ensure the longevity of their coherence.
Other systems like nuclear spins are naturally protected as they do not interact
easily with the environment. But, due to the same reason, it is harder to interact
with such systems. \r\n\r\nAfter decades of experimentation with various systems,
we are convinced that no one type of quantum system would be the best for all
the quantum applications. We would need hybrid systems which are all interconnected
- much like the current internet where all sorts of devices can all talk to each
other - but now for quantum devices. A quantum internet. \r\n\r\nOptical photons
are the best contenders to carry information for the quantum internet. They can
carry quantum information cheaply and without much loss - the same reasons which
has made them the backbone of our current internet. Following this direction,
many systems, like trapped ions, have already demonstrated successful quantum
links over a large distances using optical photons. However, some of the most
promising contenders for quantum computing which are based on microwave frequencies
have been left behind. This is because high energy optical photons can adversely
affect fragile low-energy microwave systems. \r\n\r\nIn this thesis, we present
substantial progress on this missing quantum link between microwave and optics
using electrooptical nonlinearities in lithium niobate. The nonlinearities are
enhanced by using resonant cavities for all the involved modes leading to observation
of strong direct coupling between optical and microwave frequencies. With this
strong coupling we are not only able to achieve almost 100\\% internal conversion
efficiency with low added noise, thus presenting a quantum-enabled transducer,
but also we are able to observe novel effects such as cooling of a microwave mode
using optics. The strong coupling regime also leads to direct observation of dynamical
backaction effect between microwave and optical frequencies which are studied
in detail here. Finally, we also report first observation of microwave-optics
entanglement in form of two-mode squeezed vacuum squeezed 0.7dB below vacuum level.
\r\nWith this new bridge between microwave and optics, the microwave-based quantum
technologies can finally be a part of a quantum network which is based on optical
photons - putting us one step closer to a future with quantum internet. "
acknowledged_ssus:
- _id: M-Shop
- _id: SSU
- _id: NanoFab
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Rishabh
full_name: Sahu, Rishabh
id: 47D26E34-F248-11E8-B48F-1D18A9856A87
last_name: Sahu
orcid: 0000-0001-6264-2162
citation:
ama: Sahu R. Cavity quantum electrooptics. 2023. doi:10.15479/at:ista:13175
apa: Sahu, R. (2023). Cavity quantum electrooptics. Institute of Science
and Technology Austria. https://doi.org/10.15479/at:ista:13175
chicago: Sahu, Rishabh. “Cavity Quantum Electrooptics.” Institute of Science and
Technology Austria, 2023. https://doi.org/10.15479/at:ista:13175.
ieee: R. Sahu, “Cavity quantum electrooptics,” Institute of Science and Technology
Austria, 2023.
ista: Sahu R. 2023. Cavity quantum electrooptics. Institute of Science and Technology
Austria.
mla: Sahu, Rishabh. Cavity Quantum Electrooptics. Institute of Science and
Technology Austria, 2023, doi:10.15479/at:ista:13175.
short: R. Sahu, Cavity Quantum Electrooptics, Institute of Science and Technology
Austria, 2023.
date_created: 2023-06-30T08:07:43Z
date_published: 2023-05-05T00:00:00Z
date_updated: 2023-08-24T11:16:35Z
day: '05'
ddc:
- '537'
- '535'
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: JoFi
doi: 10.15479/at:ista:13175
ec_funded: 1
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keyword:
- quantum optics
- electrooptics
- quantum networks
- quantum communication
- transduction
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
page: '202'
project:
- _id: 26336814-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '758053'
name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
call_identifier: H2020
grant_number: '899354'
name: Quantum Local Area Networks with Superconducting Qubits
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
of Superconducting Quantum Circuits
publication_identifier:
isbn:
- 978-3-99078-030-5
issn:
- 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '12900'
relation: old_edition
status: public
- id: '10924'
relation: part_of_dissertation
status: public
- id: '9114'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Johannes M
full_name: Fink, Johannes M
id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
last_name: Fink
orcid: 0000-0001-8112-028X
title: Cavity quantum electrooptics
tmp:
image: /images/cc_by_nc_sa.png
legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
BY-NC-SA 4.0)
short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '12900'
abstract:
- lang: eng
text: "About a 100 years ago, we discovered that our universe is inherently noisy,
that is, measuring any physical quantity with a precision beyond a certain point
is not possible because of an omnipresent inherent noise. We call this - the quantum
noise. Certain physical processes allow this quantum noise to get correlated in
conjugate physical variables. These quantum correlations can be used to go beyond
the potential of our inherently noisy universe and obtain a quantum advantage
over the classical applications. \r\n\r\nQuantum noise being inherent also means
that, at the fundamental level, the physical quantities are not well defined and
therefore, objects can stay in multiple states at the same time. For example,
the position of a particle not being well defined means that the particle is in
multiple positions at the same time. About 4 decades ago, we started exploring
the possibility of using objects which can be in multiple states at the same time
to increase the dimensionality in computation. Thus, the field of quantum computing
was born. We discovered that using quantum entanglement, a property closely related
to quantum correlations, can be used to speed up computation of certain problems,
such as factorisation of large numbers, faster than any known classical algorithm.
Thus began the pursuit to make quantum computers a reality. \r\n\r\nTill date,
we have explored quantum control over many physical systems including photons,
spins, atoms, ions and even simple circuits made up of superconducting material.
However, there persists one ubiquitous theme. The more readily a system interacts
with an external field or matter, the more easily we can control it. But this
also means that such a system can easily interact with a noisy environment and
quickly lose its coherence. Consequently, such systems like electron spins need
to be protected from the environment to ensure the longevity of their coherence.
Other systems like nuclear spins are naturally protected as they do not interact
easily with the environment. But, due to the same reason, it is harder to interact
with such systems. \r\n\r\nAfter decades of experimentation with various systems,
we are convinced that no one type of quantum system would be the best for all
the quantum applications. We would need hybrid systems which are all interconnected
- much like the current internet where all sorts of devices can all talk to each
other - but now for quantum devices. A quantum internet. \r\n\r\nOptical photons
are the best contenders to carry information for the quantum internet. They can
carry quantum information cheaply and without much loss - the same reasons which
has made them the backbone of our current internet. Following this direction,
many systems, like trapped ions, have already demonstrated successful quantum
links over a large distances using optical photons. However, some of the most
promising contenders for quantum computing which are based on microwave frequencies
have been left behind. This is because high energy optical photons can adversely
affect fragile low-energy microwave systems. \r\n\r\nIn this thesis, we present
substantial progress on this missing quantum link between microwave and optics
using electrooptical nonlinearities in lithium niobate. The nonlinearities are
enhanced by using resonant cavities for all the involved modes leading to observation
of strong direct coupling between optical and microwave frequencies. With this
strong coupling we are not only able to achieve almost 100\\% internal conversion
efficiency with low added noise, thus presenting a quantum-enabled transducer,
but also we are able to observe novel effects such as cooling of a microwave mode
using optics. The strong coupling regime also leads to direct observation of dynamical
backaction effect between microwave and optical frequencies which are studied
in detail here. Finally, we also report first observation of microwave-optics
entanglement in form of two-mode squeezed vacuum squeezed 0.7dB below vacuum level.
\r\nWith this new bridge between microwave and optics, the microwave-based quantum
technologies can finally be a part of a quantum network which is based on optical
photons - putting us one step closer to a future with quantum internet. "
acknowledged_ssus:
- _id: M-Shop
- _id: SSU
- _id: NanoFab
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Rishabh
full_name: Sahu, Rishabh
id: 47D26E34-F248-11E8-B48F-1D18A9856A87
last_name: Sahu
orcid: 0000-0001-6264-2162
citation:
ama: Sahu R. Cavity quantum electrooptics. 2023. doi:10.15479/at:ista:12900
apa: Sahu, R. (2023). Cavity quantum electrooptics. Institute of Science
and Technology Austria. https://doi.org/10.15479/at:ista:12900
chicago: Sahu, Rishabh. “Cavity Quantum Electrooptics.” Institute of Science and
Technology Austria, 2023. https://doi.org/10.15479/at:ista:12900.
ieee: R. Sahu, “Cavity quantum electrooptics,” Institute of Science and Technology
Austria, 2023.
ista: Sahu R. 2023. Cavity quantum electrooptics. Institute of Science and Technology
Austria.
mla: Sahu, Rishabh. Cavity Quantum Electrooptics. Institute of Science and
Technology Austria, 2023, doi:10.15479/at:ista:12900.
short: R. Sahu, Cavity Quantum Electrooptics, Institute of Science and Technology
Austria, 2023.
date_created: 2023-05-05T11:08:50Z
date_published: 2023-05-05T00:00:00Z
date_updated: 2023-08-24T11:16:35Z
day: '05'
ddc:
- '537'
- '535'
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: JoFi
doi: 10.15479/at:ista:12900
ec_funded: 1
file:
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date_updated: 2023-06-06T22:30:03Z
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file_size: 36767177
relation: source_file
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checksum: 439659ead46618147309be39d9dd5a8c
content_type: application/pdf
creator: rsahu
date_created: 2023-05-09T08:51:17Z
date_updated: 2023-07-06T11:37:40Z
file_id: '12929'
file_name: thesis_pdfa_final.pdf
file_size: 17501990
relation: main_file
file_date_updated: 2023-07-06T11:37:40Z
has_accepted_license: '1'
keyword:
- quantum optics
- electrooptics
- quantum networks
- quantum communication
- transduction
language:
- iso: eng
month: '05'
oa_version: Published Version
page: '190'
project:
- _id: 26336814-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '758053'
name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: 9B868D20-BA93-11EA-9121-9846C619BF3A
call_identifier: H2020
grant_number: '899354'
name: Quantum Local Area Networks with Superconducting Qubits
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
of Superconducting Quantum Circuits
publication_identifier:
isbn:
- 978-3-99078-030-5
issn:
- 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '13175'
relation: new_edition
status: public
- id: '10924'
relation: part_of_dissertation
status: public
- id: '9114'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Johannes M
full_name: Fink, Johannes M
id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
last_name: Fink
orcid: 0000-0001-8112-028X
title: Cavity quantum electrooptics
tmp:
image: /images/cc_by_nc_sa.png
legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
BY-NC-SA 4.0)
short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '12732'
abstract:
- lang: eng
text: "Nonergodic systems, whose out-of-equilibrium dynamics fail to thermalize,
provide a fascinating research direction both for fundamental reasons and for
application in state of the art quantum devices.\r\nGoing beyond the description
of statistical mechanics, ergodicity breaking yields a new paradigm in quantum
many-body physics, introducing novel phases of matter with no counterpart at equilibrium.\r\nIn
this Thesis, we address different open questions in the field, focusing on disorder-induced
many-body localization (MBL) and on weak ergodicity breaking in kinetically constrained
models.\r\nIn particular, we contribute to the debate about transport in kinetically
constrained models, studying the effect of $U(1)$ conservation and inversion-symmetry
breaking in a family of quantum East models.\r\nUsing tensor network techniques,
we analyze the dynamics of large MBL systems beyond the limit of exact numerical
methods.\r\nIn this setting, we approach the debated topic of the coexistence
of localized and thermal eigenstates separated by energy thresholds known as many-body
mobility edges.\r\nInspired by recent experiments, our work further investigates
the localization of a small bath induced by the coupling to a large localized
chain, the so-called MBL proximity effect.\r\n\r\nIn the first Chapter, we introduce
a family of particle-conserving kinetically constrained models, inspired by the
quantum East model.\r\nThe system we study features strong inversion-symmetry
breaking, due to the nature of the correlated hopping.\r\nWe show that these models
host so-called quantum Hilbert space fragmentation, consisting of disconnected
subsectors in an entangled basis, and further provide an analytical description
of this phenomenon.\r\nWe further probe its effect on dynamics of simple product
states, showing revivals in fidelity and local observalbes.\r\nThe study of dynamics
within the largest subsector reveals an anomalous transient superdiffusive behavior
crossing over to slow logarithmic dynamics at later times.\r\nThis work suggests
that particle conserving constrained models with inversion-symmetry breaking realize
new universality classes of dynamics and invite their further theoretical and
experimental studies.\r\n\r\nNext, we use kinetic constraints and disorder to
design a model with many-body mobility edges in particle density.\r\nThis feature
allows to study the dynamics of localized and thermal states in large systems
beyond the limitations of previous studies.\r\nThe time-evolution shows typical
signatures of localization at small densities, replaced by thermal behavior at
larger densities.\r\nOur results provide evidence in favor of the stability of
many-body mobility edges, which was recently challenged by a theoretical argument.\r\nTo
support our findings, we probe the mechanism proposed as a cause of delocalization
in many-body localized systems with mobility edges suggesting its ineffectiveness
in the model studied.\r\n\r\nIn the last Chapter of this Thesis, we address the
topic of many-body localization proximity effect.\r\nWe study a model inspired
by recent experiments, featuring Anderson localized coupled to a small bath of
free hard-core bosons.\r\nThe interaction among the two particle species results
in non-trivial dynamics, which we probe using tensor network techniques.\r\nOur
simulations show convincing evidence of many-body localization proximity effect
when the bath is composed by a single free particle and interactions are strong.\r\nWe
furthter observe an anomalous entanglement dynamics, which we explain through
a phenomenological theory.\r\nFinally, we extract highly excited eigenstates of
large systems, providing supplementary evidence in favor of our findings."
acknowledged_ssus:
- _id: ScienComp
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Pietro
full_name: Brighi, Pietro
id: 4115AF5C-F248-11E8-B48F-1D18A9856A87
last_name: Brighi
orcid: 0000-0002-7969-2729
citation:
ama: Brighi P. Ergodicity breaking in disordered and kinetically constrained quantum
many-body systems. 2023. doi:10.15479/at:ista:12732
apa: Brighi, P. (2023). Ergodicity breaking in disordered and kinetically constrained
quantum many-body systems. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:12732
chicago: Brighi, Pietro. “Ergodicity Breaking in Disordered and Kinetically Constrained
Quantum Many-Body Systems.” Institute of Science and Technology Austria, 2023.
https://doi.org/10.15479/at:ista:12732.
ieee: P. Brighi, “Ergodicity breaking in disordered and kinetically constrained
quantum many-body systems,” Institute of Science and Technology Austria, 2023.
ista: Brighi P. 2023. Ergodicity breaking in disordered and kinetically constrained
quantum many-body systems. Institute of Science and Technology Austria.
mla: Brighi, Pietro. Ergodicity Breaking in Disordered and Kinetically Constrained
Quantum Many-Body Systems. Institute of Science and Technology Austria, 2023,
doi:10.15479/at:ista:12732.
short: P. Brighi, Ergodicity Breaking in Disordered and Kinetically Constrained
Quantum Many-Body Systems, Institute of Science and Technology Austria, 2023.
date_created: 2023-03-17T13:30:48Z
date_published: 2023-03-21T00:00:00Z
date_updated: 2023-09-20T10:44:12Z
day: '21'
ddc:
- '530'
degree_awarded: PhD
department:
- _id: GradSch
- _id: MaSe
doi: 10.15479/at:ista:12732
ec_funded: 1
file:
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checksum: 5d2de651ef9449c1b8dc27148ca74777
content_type: application/zip
creator: pbrighi
date_created: 2023-03-23T16:42:56Z
date_updated: 2023-03-23T16:42:56Z
file_id: '12753'
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file_size: 42167561
relation: source_file
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checksum: 7caa153d4a5b0873a79358787d2dfe1e
content_type: application/pdf
creator: pbrighi
date_created: 2023-03-23T16:43:14Z
date_updated: 2023-03-23T16:43:14Z
file_id: '12754'
file_name: Thesis_PBrighi.pdf
file_size: 13977000
relation: main_file
success: 1
file_date_updated: 2023-03-23T16:43:14Z
has_accepted_license: '1'
language:
- iso: eng
month: '03'
oa: 1
oa_version: None
page: '158'
project:
- _id: 23841C26-32DE-11EA-91FC-C7463DDC885E
call_identifier: H2020
grant_number: '850899'
name: 'Non-Ergodic Quantum Matter: Universality, Dynamics and Control'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '11470'
relation: part_of_dissertation
status: public
- id: '8308'
relation: part_of_dissertation
status: public
- id: '11469'
relation: part_of_dissertation
status: public
- id: '12750'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Maksym
full_name: Serbyn, Maksym
id: 47809E7E-F248-11E8-B48F-1D18A9856A87
last_name: Serbyn
orcid: 0000-0002-2399-5827
title: Ergodicity breaking in disordered and kinetically constrained quantum many-body
systems
tmp:
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legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
BY-NC-SA 4.0)
short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '13081'
abstract:
- lang: eng
text: During development, tissues undergo changes in size and shape to form functional
organs. Distinct cellular processes such as cell division and cell rearrangements
underlie tissue morphogenesis. Yet how the distinct processes are controlled and
coordinated, and how they contribute to morphogenesis is poorly understood. In
our study, we addressed these questions using the developing mouse neural tube.
This epithelial organ transforms from a flat epithelial sheet to an epithelial
tube while increasing in size and undergoing morpho-gen-mediated patterning. The
extent and mechanism of neural progenitor rearrangement within the developing
mouse neuroepithelium is unknown. To investigate this, we per-formed high resolution
lineage tracing analysis to quantify the extent of epithelial rear-rangement at
different stages of neural tube development. We quantitatively described the relationship
between apical cell size with cell cycle dependent interkinetic nuclear migra-tions
(IKNM) and performed high cellular resolution live imaging of the neuroepithelium
to study the dynamics of junctional remodeling. Furthermore, developed a vertex
model of the neuroepithelium to investigate the quantitative contribution of cell
proliferation, cell differentiation and mechanical properties to the epithelial
rearrangement dynamics and validated the model predictions through functional
experiments. Our analysis revealed that at early developmental stages, the apical
cell area kinetics driven by IKNM induce high lev-els of cell rearrangements in
a regime of high junctional tension and contractility. After E9.5, there is a
sharp decline in the extent of cell rearrangements, suggesting that the epi-thelium
transitions from a fluid-like to a solid-like state. We found that this transition
is regulated by the growth rate of the tissue, rather than by changes in cell-cell
adhesion and contractile forces. Overall, our study provides a quantitative description
of the relationship between tissue growth, cell cycle dynamics, epithelia rearrangements
and the emergent tissue material properties, and novel insights on how epithelial
cell dynamics influences tissue morphogenesis.
acknowledged_ssus:
- _id: Bio
- _id: LifeSc
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Laura
full_name: Bocanegra, Laura
id: 4896F754-F248-11E8-B48F-1D18A9856A87
last_name: Bocanegra
citation:
ama: Bocanegra L. Epithelial dynamics during mouse neural tube development. 2023.
doi:10.15479/at:ista:13081
apa: Bocanegra, L. (2023). Epithelial dynamics during mouse neural tube development.
Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:13081
chicago: Bocanegra, Laura. “Epithelial Dynamics during Mouse Neural Tube Development.”
Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:13081.
ieee: L. Bocanegra, “Epithelial dynamics during mouse neural tube development,”
Institute of Science and Technology Austria, 2023.
ista: Bocanegra L. 2023. Epithelial dynamics during mouse neural tube development.
Institute of Science and Technology Austria.
mla: Bocanegra, Laura. Epithelial Dynamics during Mouse Neural Tube Development.
Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:13081.
short: L. Bocanegra, Epithelial Dynamics during Mouse Neural Tube Development, Institute
of Science and Technology Austria, 2023.
date_created: 2023-05-23T19:10:42Z
date_published: 2023-05-23T00:00:00Z
date_updated: 2023-10-04T11:14:04Z
day: '23'
ddc:
- '570'
degree_awarded: PhD
department:
- _id: GradSch
- _id: AnKi
doi: 10.15479/at:ista:13081
file:
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date_updated: 2023-05-25T06:32:16Z
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has_accepted_license: '1'
language:
- iso: eng
license: https://creativecommons.org/licenses/by-nc-nd/4.0/
month: '05'
oa_version: Published Version
page: '93'
publication_identifier:
issn:
- 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '9349'
relation: part_of_dissertation
status: public
- id: '12837'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Anna
full_name: Kicheva, Anna
id: 3959A2A0-F248-11E8-B48F-1D18A9856A87
last_name: Kicheva
orcid: 0000-0003-4509-4998
title: Epithelial dynamics during mouse neural tube development
tmp:
image: /images/cc_by_nc_nd.png
legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
(CC BY-NC-ND 4.0)
short: CC BY-NC-ND (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '13331'
abstract:
- lang: eng
text: "The extension of extremal combinatorics to the setting of exterior algebra
is a work\r\nin progress that gained attention recently. In this thesis, we study
the combinatorial structure of exterior algebra by introducing a dictionary that
translates the notions from the set systems into the framework of exterior algebra.
We show both generalizations of celebrated Erdös--Ko--Rado theorem and Hilton--Milner
theorem to the setting of exterior algebra in the simplest non-trivial case of
two-forms.\r\n"
alternative_title:
- ISTA Master's Thesis
article_processing_charge: No
author:
- first_name: Seyda
full_name: Köse, Seyda
id: 8ba3170d-dc85-11ea-9058-c4251c96a6eb
last_name: Köse
citation:
ama: Köse S. Exterior algebra and combinatorics. 2023. doi:10.15479/at:ista:13331
apa: Köse, S. (2023). Exterior algebra and combinatorics. Institute of Science
and Technology Austria. https://doi.org/10.15479/at:ista:13331
chicago: Köse, Seyda. “Exterior Algebra and Combinatorics.” Institute of Science
and Technology Austria, 2023. https://doi.org/10.15479/at:ista:13331.
ieee: S. Köse, “Exterior algebra and combinatorics,” Institute of Science and Technology
Austria, 2023.
ista: Köse S. 2023. Exterior algebra and combinatorics. Institute of Science and
Technology Austria.
mla: Köse, Seyda. Exterior Algebra and Combinatorics. Institute of Science
and Technology Austria, 2023, doi:10.15479/at:ista:13331.
short: S. Köse, Exterior Algebra and Combinatorics, Institute of Science and Technology
Austria, 2023.
date_created: 2023-07-31T10:20:55Z
date_published: 2023-07-31T00:00:00Z
date_updated: 2023-10-04T11:54:56Z
day: '31'
ddc:
- '510'
- '516'
degree_awarded: MS
department:
- _id: GradSch
- _id: UlWa
doi: 10.15479/at:ista:13331
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file_size: 28684
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creator: skoese
date_created: 2023-08-03T15:28:55Z
date_updated: 2023-08-03T15:28:55Z
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file_name: thesis-pdfa.pdf
file_size: 4953418
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file_date_updated: 2023-08-03T15:28:55Z
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language:
- iso: eng
month: '07'
oa: 1
oa_version: Published Version
page: '26'
publication_identifier:
issn:
- 2791-4585
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '12680'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Uli
full_name: Wagner, Uli
id: 36690CA2-F248-11E8-B48F-1D18A9856A87
last_name: Wagner
orcid: 0000-0002-1494-0568
title: Exterior algebra and combinatorics
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '14422'
abstract:
- lang: eng
text: "Animals exhibit a remarkable ability to learn and remember new behaviors,
skills, and associations throughout their lifetime. These capabilities are made
possible thanks to a variety of\r\nchanges in the brain throughout adulthood,
regrouped under the term \"plasticity\". Some cells\r\nin the brain —neurons—
and specifically changes in the connections between neurons, the\r\nsynapses,
were shown to be crucial for the formation, selection, and consolidation of memories\r\nfrom
past experiences. These ongoing changes of synapses across time are called synaptic\r\nplasticity.
Understanding how a myriad of biochemical processes operating at individual\r\nsynapses
can somehow work in concert to give rise to meaningful changes in behavior is
a\r\nfascinating problem and an active area of research.\r\nHowever, the experimental
search for the precise plasticity mechanisms at play in the brain\r\nis daunting,
as it is difficult to control and observe synapses during learning. Theoretical\r\napproaches
have thus been the default method to probe the plasticity-behavior connection.
Such\r\nstudies attempt to extract unifying principles across synapses and model
all observed synaptic\r\nchanges using plasticity rules: equations that govern
the evolution of synaptic strengths across\r\ntime in neuronal network models.
These rules can use many relevant quantities to determine\r\nthe magnitude of
synaptic changes, such as the precise timings of pre- and postsynaptic\r\naction
potentials, the recent neuronal activity levels, the state of neighboring synapses,
etc.\r\nHowever, analytical studies rely heavily on human intuition and are forced
to make simplifying\r\nassumptions about plasticity rules.\r\nIn this thesis,
we aim to assist and augment human intuition in this search for plasticity rules.\r\nWe
explore whether a numerical approach could automatically discover the plasticity
rules\r\nthat elicit desired behaviors in large networks of interconnected neurons.
This approach is\r\ndubbed meta-learning synaptic plasticity: learning plasticity
rules which themselves will make\r\nneuronal networks learn how to solve a desired
task. We first write all the potential plasticity\r\nmechanisms to consider using
a single expression with adjustable parameters. We then optimize\r\nthese plasticity
parameters using evolutionary strategies or Bayesian inference on tasks known\r\nto
involve synaptic plasticity, such as familiarity detection and network stabilization.\r\nWe
show that these automated approaches are powerful tools, able to complement established\r\nanalytical
methods. By comprehensively screening plasticity rules at all synapse types in\r\nrealistic,
spiking neuronal network models, we discover entire sets of degenerate plausible\r\nplasticity
rules that reliably elicit memory-related behaviors. Our approaches allow for
more\r\nrobust experimental predictions, by abstracting out the idiosyncrasies
of individual plasticity\r\nrules, and provide fresh insights on synaptic plasticity
in spiking network models.\r\n"
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Basile J
full_name: Confavreux, Basile J
id: C7610134-B532-11EA-BD9F-F5753DDC885E
last_name: Confavreux
citation:
ama: 'Confavreux BJ. Synapseek: Meta-learning synaptic plasticity rules. 2023. doi:10.15479/at:ista:14422'
apa: 'Confavreux, B. J. (2023). Synapseek: Meta-learning synaptic plasticity
rules. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:14422'
chicago: 'Confavreux, Basile J. “Synapseek: Meta-Learning Synaptic Plasticity Rules.”
Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:14422.'
ieee: 'B. J. Confavreux, “Synapseek: Meta-learning synaptic plasticity rules,” Institute
of Science and Technology Austria, 2023.'
ista: 'Confavreux BJ. 2023. Synapseek: Meta-learning synaptic plasticity rules.
Institute of Science and Technology Austria.'
mla: 'Confavreux, Basile J. Synapseek: Meta-Learning Synaptic Plasticity Rules.
Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:14422.'
short: 'B.J. Confavreux, Synapseek: Meta-Learning Synaptic Plasticity Rules, Institute
of Science and Technology Austria, 2023.'
date_created: 2023-10-12T14:13:25Z
date_published: 2023-10-12T00:00:00Z
date_updated: 2023-10-18T09:20:56Z
day: '12'
ddc:
- '610'
degree_awarded: PhD
department:
- _id: GradSch
- _id: TiVo
doi: 10.15479/at:ista:14422
ec_funded: 1
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file_size: 30599717
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creator: cchlebak
date_created: 2023-10-18T07:38:34Z
date_updated: 2023-10-18T07:56:08Z
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file_name: Confavreux Thesis.zip
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has_accepted_license: '1'
language:
- iso: eng
month: '10'
oa_version: Published Version
page: '148'
project:
- _id: 0aacfa84-070f-11eb-9043-d7eb2c709234
call_identifier: H2020
grant_number: '819603'
name: Learning the shape of synaptic plasticity rules for neuronal architectures
and function through machine learning.
publication_identifier:
issn:
- 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '9633'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Tim P
full_name: Vogels, Tim P
id: CB6FF8D2-008F-11EA-8E08-2637E6697425
last_name: Vogels
orcid: 0000-0003-3295-6181
title: 'Synapseek: Meta-learning synaptic plasticity rules'
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BY-NC-SA 4.0)
short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '14374'
abstract:
- lang: eng
text: "Superconductivity has many important applications ranging from levitating
trains over qubits to MRI scanners. The phenomenon is successfully modeled by
Bardeen-Cooper-Schrieffer (BCS) theory. From a mathematical perspective, BCS theory
has been studied extensively for systems without boundary. However, little is
known in the presence of boundaries. With the help of numerical methods physicists
observed that the critical temperature may increase in the presence of a boundary.
The goal of this thesis is to understand the influence of boundaries on the critical
temperature in BCS theory and to give a first rigorous justification of these
observations. On the way, we also study two-body Schrödinger operators on domains
with boundaries and prove additional results for superconductors without boundary.\r\n\r\nBCS
theory is based on a non-linear functional, where the minimizer indicates whether
the system is superconducting or in the normal, non-superconducting state. By
considering the Hessian of the BCS functional at the normal state, one can analyze
whether the normal state is possibly a minimum of the BCS functional and estimate
the critical temperature. The Hessian turns out to be a linear operator resembling
a Schrödinger operator for two interacting particles, but with more complicated
kinetic energy. As a first step, we study the two-body Schrödinger operator in
the presence of boundaries.\r\nFor Neumann boundary conditions, we prove that
the addition of a boundary can create new eigenvalues, which correspond to the
two particles forming a bound state close to the boundary.\r\n\r\nSecond, we need
to understand superconductivity in the translation invariant setting. While in
three dimensions this has been extensively studied, there is no mathematical literature
for the one and two dimensional cases. In dimensions one and two, we compute the
weak coupling asymptotics of the critical temperature and the energy gap in the
translation invariant setting. We also prove that their ratio is independent of
the microscopic details of the model in the weak coupling limit; this property
is referred to as universality.\r\n\r\nIn the third part, we study the critical
temperature of superconductors in the presence of boundaries. We start by considering
the one-dimensional case of a half-line with contact interaction. Then, we generalize
the results to generic interactions and half-spaces in one, two and three dimensions.
Finally, we compare the critical temperature of a quarter space in two dimensions
to the critical temperatures of a half-space and of the full space."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Barbara
full_name: Roos, Barbara
id: 5DA90512-D80F-11E9-8994-2E2EE6697425
last_name: Roos
orcid: 0000-0002-9071-5880
citation:
ama: Roos B. Boundary superconductivity in BCS theory. 2023. doi:10.15479/at:ista:14374
apa: Roos, B. (2023). Boundary superconductivity in BCS theory. Institute
of Science and Technology Austria. https://doi.org/10.15479/at:ista:14374
chicago: Roos, Barbara. “Boundary Superconductivity in BCS Theory.” Institute of
Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:14374.
ieee: B. Roos, “Boundary superconductivity in BCS theory,” Institute of Science
and Technology Austria, 2023.
ista: Roos B. 2023. Boundary superconductivity in BCS theory. Institute of Science
and Technology Austria.
mla: Roos, Barbara. Boundary Superconductivity in BCS Theory. Institute of
Science and Technology Austria, 2023, doi:10.15479/at:ista:14374.
short: B. Roos, Boundary Superconductivity in BCS Theory, Institute of Science and
Technology Austria, 2023.
date_created: 2023-09-28T14:23:04Z
date_published: 2023-09-30T00:00:00Z
date_updated: 2023-10-27T10:37:30Z
day: '30'
ddc:
- '515'
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: RoSe
doi: 10.15479/at:ista:14374
ec_funded: 1
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checksum: ef039ffc3de2cb8dee5b14110938e9b6
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creator: broos
date_created: 2023-10-06T11:35:56Z
date_updated: 2023-10-06T11:35:56Z
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creator: broos
date_created: 2023-10-06T11:38:01Z
date_updated: 2023-10-06T11:38:01Z
file_id: '14399'
file_name: Version5.zip
file_size: 4691734
relation: source_file
file_date_updated: 2023-10-06T11:38:01Z
has_accepted_license: '1'
language:
- iso: eng
month: '09'
oa: 1
oa_version: Published Version
page: '206'
project:
- _id: 25C6DC12-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '694227'
name: Analysis of quantum many-body systems
- _id: bda63fe5-d553-11ed-ba76-a16e3d2f256b
grant_number: I06427
name: Mathematical Challenges in BCS Theory of Superconductivity
publication_identifier:
issn:
- 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '13207'
relation: part_of_dissertation
status: public
- id: '10850'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Robert
full_name: Seiringer, Robert
id: 4AFD0470-F248-11E8-B48F-1D18A9856A87
last_name: Seiringer
orcid: 0000-0002-6781-0521
title: Boundary superconductivity in BCS theory
tmp:
image: /images/cc_by_nc_sa.png
legal_code_url: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode
name: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC
BY-NC-SA 4.0)
short: CC BY-NC-SA (4.0)
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...