@article{1769,
abstract = {We present an ideal realization of the Tavis-Cummings model in the absence of atom number and coupling fluctuations by embedding a discrete number of fully controllable superconducting qubits at fixed positions into a transmission line resonator. Measuring the vacuum Rabi mode splitting with one, two, and three qubits strongly coupled to the cavity field, we explore both bright and dark dressed collective multiqubit states and observe the discrete N scaling of the collective dipole coupling strength. Our experiments demonstrate a novel approach to explore collective states, such as the W state, in a fully globally and locally controllable quantum system. Our scalable approach is interesting for solid-state quantum information processing and for fundamental multiatom quantum optics experiments with fixed atom numbers.},
author = {Johannes Fink and Bianchetti, R and Baur, Matthias P and Göppl, M and Steffen, L. Kraig and Filipp, Stefan and Leek, Peter J and Blais, Alexandre and Wallraff, Andreas},
journal = {Physical Review Letters},
number = {8},
publisher = {American Physical Society},
title = {{Dressed collective qubit states and the Tavis-Cummings model in circuit QED}},
doi = {10.1103/PhysRevLett.103.083601},
volume = {103},
year = {2009},
}
@article{1770,
abstract = {The quantum state of a superconducting qubit nonresonantly coupled to a transmission line resonator can be determined by measuring the quadrature amplitudes of an electromagnetic field transmitted through the resonator. We present experiments in which we analyze in detail the dynamics of the transmitted field as a function of the measurement frequency for both weak continuous and pulsed measurements. We find excellent agreement between our data and calculations based on a set of Bloch-type differential equations for the cavity field derived from the dispersive Jaynes-Cummings Hamiltonian including dissipation. We show that the measured system response can be used to construct a measurement operator from which the qubit population can be inferred accurately. Such a measurement operator can be used in tomographic methods to reconstruct single and multiqubit states in ensemble-averaged measurements.},
author = {Bianchetti, R and Filipp, Stefan and Baur, Matthias P and Johannes Fink and Göppl, M and Leek, Peter J and Steffen, L. Kraig and Blais, Alexandre and Wallraff, Andreas},
journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
number = {4},
publisher = {American Physical Society},
title = {{Dynamics of dispersive single-qubit readout in circuit quantum electrodynamics}},
doi = {10.1103/PhysRevA.80.043840},
volume = {80},
year = {2009},
}
@article{1771,
abstract = {The exceptionally strong coupling realizable between superconducting qubits and photons stored in an on-chip microwave resonator allows for the detailed study of matter-light interactions in the realm of circuit quantum electrodynamics (QED). Here we investigate the resonant interaction between a single transmon-type multilevel artificial atom and weak thermal and coherent fields. We explore up to three photon dressed states of the coupled system in a linear response heterodyne transmission measurement. The results are in good quantitative agreement with a generalized Jaynes-Cummings model. Our data indicate that the role of thermal fields in resonant cavity QED can be studied in detail using superconducting circuits.},
author = {Johannes Fink and Baur, Matthias P and Bianchetti, R and Filipp, Stefan and Göppl, M and Leek, Peter J and Steffen, L. Kraig and Blais, Alexandre and Wallraff, Andreas},
journal = {Physica Scripta T},
publisher = {IOP Publishing Ltd.},
title = {{Thermal excitation of multi-photon dressed states in circuit quantum electrodynamics}},
doi = {10.1088/0031-8949/2009/T137/014013},
volume = {T137},
year = {2009},
}
@article{1825,
abstract = {Many membrane channels and receptors exhibit adaptive, or desensitized, response to a strong sustained input stimulus. A key mechanism that underlies this response is the slow, activity-dependent removal of responding molecules to a pool which is unavailable to respond immediately to the input. This mechanism is implemented in different ways in various biological systems and has traditionally been studied separately for each. Here we highlight the common aspects of this principle, shared by many biological systems, and suggest a unifying theoretical framework. We study theoretically a class of models which describes the general mechanism and allows us to distinguish its universal from system-specific features. We show that under general conditions, regardless of the details of kinetics, molecule availability encodes an averaging over past activity and feeds back multiplicatively on the system output. The kinetics of recovery from unavailability determines the effective memory kernel inside the feedback branch, giving rise to a variety of system-specific forms of adaptive response—precise or input-dependent, exponential or power-law—as special cases of the same model. },
author = {Tamar Friedlander and Brenner, Naama},
journal = {PNAS},
number = {52},
pages = {22558 -- 22563},
publisher = {National Academy of Sciences},
title = {{Adaptive response by state-dependent inactivation}},
doi = {10.1073/pnas.0902146106 },
volume = {106},
year = {2009},
}
@article{2119,
abstract = {Let (E, H, μ) be an abstract Wiener space and let DV : = V D, where D denotes the Malliavin derivative and V is a closed and densely defined operator from H into another Hilbert space under(H, {combining low line}). Given a bounded operator B on under(H, {combining low line}), coercive on the range over(R (V), -), we consider the operators A : = V* B V in H and under(A, {combining low line}) : = V V* B in under(H, {combining low line}), as well as the realisations of the operators L : = DV* B DV and under(L, {combining low line}) : = DV DV* B in Lp (E, μ) and Lp (E, μ ; under(H, {combining low line})) respectively, where 1 < p < ∞. Our main result asserts that the following four assertions are equivalent: (1)D (sqrt(L)) = D (DV) with {norm of matrix} sqrt(L) f {norm of matrix}p {minus tilde} {norm of matrix} DV f {norm of matrix}p for f ∈ D (sqrt(L));(2)under(L, {combining low line}) admits a bounded H∞-functional calculus on over(R (DV), -);(3)D (sqrt(A)) = D (V) with {norm of matrix} sqrt(A) h {norm of matrix} {minus tilde} {norm of matrix} V h {norm of matrix} for h ∈ D (sqrt(A));(4)under(A, {combining low line}) admits a bounded H∞-functional calculus on over(R (V), -). Moreover, if these conditions are satisfied, then D (L) = D (DV2) ∩ D (DA). The equivalence (1)-(4) is a non-symmetric generalisation of the classical Meyer inequalities of Malliavin calculus (where under(H, {combining low line}) = H, V = I, B = frac(1, 2) I). A one-sided version of (1)-(4), giving Lp-boundedness of the Riesz transform DV / sqrt(L) in terms of a square function estimate, is also obtained. As an application let -A generate an analytic C0-contraction semigroup on a Hilbert space H and let -L be the Lp-realisation of the generator of its second quantisation. Our results imply that two-sided bounds for the Riesz transform of L are equivalent with the Kato square root property for A. The boundedness of the Riesz transform is used to obtain an Lp-domain characterisation for the operator L.},
author = {Jan Maas and van Neerven, Jan M},
journal = {Journal of Functional Analysis},
number = {8},
pages = {2410 -- 2475},
publisher = {Academic Press},
title = {{Boundedness of Riesz transforms for elliptic operators on abstract Wiener spaces}},
doi = {10.1016/j.jfa.2009.07.001},
volume = {257},
year = {2009},
}
@article{2137,
abstract = {Relying on the quantization rule of Raab and Friedrich [Phys. Rev. A (2009) in press], we derive simple and accurate formulae for the number of rotational states supported by a weakly bound vibrational level of a diatomic molecular ion. We also provide analytic estimates of the rotational constants of any such levels up to threshold for dissociation and obtain a criterion for determining whether a given weakly bound vibrational level is rotationless. The results depend solely on the long-range part of the molecular potential.},
author = {Mikhail Lemeshko and Frierich, Bretislav},
journal = {Journal of Atomic and Molecular Sciences},
number = {1},
pages = {41 -- 47},
publisher = {Global Science Press},
title = {{Rotational structure of weakly bound molecular ions}},
doi = {10.4208/jams.101009.110209a},
volume = {1},
year = {2009},
}
@article{2149,
abstract = {We investigate the effects of a magnetic field on the dynamics of rotationally inelastic collisions of open-shell molecules (Σ2, Σ3, and Π2) with closed-shell atoms. Our treatment makes use of the Fraunhofer model of matter wave scattering and its recent extension to collisions in electric [M. Lemeshko and B. Friedrich, J. Chem. Phys. 129, 024301 (2008)] and radiative fields [M. Lemeshko and B. Friedrich, Int. J. Mass. Spec. 280, 19 (2009)]. A magnetic field aligns the molecule in the space-fixed frame and thereby alters the effective shape of the diffraction target. This significantly affects the differential and integral scattering cross sections. We exemplify our treatment by evaluating the magnetic-field-dependent scattering characteristics of the He-CaH (XΣ+2), He-O2 (XΣ–3), and He-OH (XΠΩ2) systems at thermal collision energies. Since the cross sections can be obtained for different orientations of the magnetic field with respect to the relative velocity vector, the model also offers predictions about the frontal-versus-lateral steric asymmetry of the collisions. The steric asymmetry is found to be almost negligible for the He-OH system, weak for the He-CaH collisions, and strong for the He-O2. While odd ΔM transitions dominate the He-OH [J=3/2,f→J′,e/f] integral cross sections in a magnetic field parallel to the relative velocity vector, even ΔM transitions prevail in the case of the He-CaH (X2Σ+) and He-O2 (XΣ−3) collision systems. For the latter system, the magnetic field opens inelastic channels that are closed in the absence of the field. These involve the transitions N=1,J=0→N′, J′ with J′=N′.},
author = {Mikhail Lemeshko and Friedrich, Břetislav},
journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
number = {1},
publisher = {American Physical Society},
title = {{Collisions of paramagnetic molecules in magnetic fields: An analytic model based on Fraunhofer diffraction of matter waves}},
doi = {10.1103/PhysRevA.79.012718},
volume = {79},
year = {2009},
}
@article{2150,
abstract = {We examine the effects of a linearly polarized nonresonant radiative field on the dynamics of rotationally inelastic Na+ + N2 collisions at eV collision energies. Our treatment is based on the Fraunhofer model of matter wave scattering and its recent extension to collisions in electric fields [M. Lemeshko, B. Friedrich, J. Chem. Phys. 129 (2008) 024301]. The nonresonant radiative field changes the effective shape of the target molecule by aligning it in the space-fixed frame. This markedly alters the differential and integral scattering cross-sections. As the cross-sections can be evaluated for a polarization of the radiative field collinear or perpendicular to the relative velocity vector, the model also offers predictions about steric asymmetry of the collisions.},
author = {Mikhail Lemeshko and Friedrich, Břetislav},
journal = {International Journal of Mass Spectrometry},
number = {1-3},
pages = {19 -- 25},
publisher = {Elsevier},
title = {{The effect of a nonresonant radiative field on low-energy rotationally inelastic Na+ + N2 collisions}},
doi = {10.1016/j.ijms.2008.06.010 },
volume = {280},
year = {2009},
}
@article{2191,
abstract = {By making use of the quantization rule of Raab and Friedrich [Phys. Rev. A 78, 022707 (2008)], we derive simple and accurate formulae for the number of rotational states supported by a weakly bound vibrational level of a diatomic molecule and the rotational constants of any such levels up to the threshold, and provide a criterion for determining whether a given weakly bound vibrational level is rotationless. The results depend solely on the long-range part of the molecular potential and are applicable to halo molecules. },
author = {Mikhail Lemeshko and Friedrich, Břetislav},
journal = {Physical Review A - Atomic, Molecular, and Optical Physics},
number = {5},
publisher = {American Physical Society},
title = {{Rotational and rotationless states of weakly bound molecules}},
doi = {10.1103/PhysRevA.79.050501},
volume = {79},
year = {2009},
}
@article{2192,
abstract = {We develop an analytic model of thermal state-to-state rotationally inelastic collisions of asymmetric-top molecules with closed-shell atoms in electric fields and apply it to the Ar-H2O collision system. The predicted cross sections as well as the steric asymmetry of the collisions show at fields up to 150 kV/cm characteristic field-dependent features which can be experimentally tested. Particularly suitable candidates for such tests are the 000 → 220 and 101→ 221 channels, arising from the relaxation of the field-free selection rules due to the hybridization of J states by the field. Averaging over the M' product channels is found to largely obliterate the orientation effects brought about by the field.},
author = {Mikhail Lemeshko and Friedrich, Břetislav},
journal = {Journal of Physical Chemistry A},
number = {52},
pages = {15055 -- 15063},
publisher = {American Chemical Society},
title = {{Model analysis of rotationally inelastic Ar + H2O scattering in an electric field}},
doi = {10.1021/jp9051598},
volume = {113},
year = {2009},
}
@article{2193,
abstract = {We show that weakly bound molecules can be probed by "shaking" in a pulsed nonresonant laser field. The field introduces a centrifugal term which expels the highest vibrational level from the potential that binds it. Our numerical simulations applied to the Rb2 and KRb Feshbach molecules indicate that shaking by feasible laser pulses can be used to accurately recover the square of the vibrational wave function and, by inversion, also the long-range part of the molecular potential.},
author = {Mikhail Lemeshko and Friedrich, Břetislav},
journal = {Physical Review Letters},
number = {5},
publisher = {American Physical Society},
title = {{Probing weakly bound molecules with nonresonant light}},
doi = {10.1103/PhysRevLett.103.053003},
volume = {103},
year = {2009},
}
@misc{5392,
abstract = {We consider probabilistic automata on infinite words with acceptance defined by safety, reachability, Büchi, coBüchi and limit-average conditions. We consider quantitative and qualitative decision problems. We present extensions and adaptations of proofs of [GO09] and present a precise characterization of the decidability and undecidability frontier of the quantitative and qualitative decision problems.},
author = {Chatterjee, Krishnendu},
issn = {2664-1690},
pages = {17},
publisher = {IST Austria},
title = {{Probabilistic automata on infinite words: Decidability and undecidability results}},
doi = {10.15479/AT:IST-2009-0004},
year = {2009},
}
@misc{5393,
abstract = {Gist is a tool that (a) solves the qualitative analysis problem of turn-based probabilistic games with ω-regular objectives; and (b) synthesizes reasonable environment assumptions for synthesis of unrealizable specifications. Our tool provides efficient implementations of several reduction based techniques to solve turn-based probabilistic games, and uses the analysis of turn-based probabilistic games for synthesizing environment assumptions for unrealizable specifications.},
author = {Chatterjee, Krishnendu and Henzinger, Thomas A and Jobstmann, Barbara and Radhakrishna, Arjun},
issn = {2664-1690},
pages = {12},
publisher = {IST Austria},
title = {{Gist: A solver for probabilistic games}},
doi = {10.15479/AT:IST-2009-0003},
year = {2009},
}
@misc{5394,
abstract = {We consider two-player games played on graphs with request-response and finitary Streett objectives. We show these games are PSPACE-hard, improving the previous known NP-hardness. We also improve the lower bounds on memory required by the winning strategies for the players.},
author = {Chatterjee, Krishnendu and Henzinger, Thomas A and Horn, Florian},
issn = {2664-1690},
pages = {11},
publisher = {IST Austria},
title = {{Improved lower bounds for request-response and finitary Streett games}},
doi = {10.15479/AT:IST-2009-0002},
year = {2009},
}
@misc{5395,
abstract = {We study observation-based strategies for partially-observable Markov decision processes (POMDPs) with omega-regular objectives. An observation-based strategy relies on partial information about the history of a play, namely, on the past sequence of observa- tions. We consider the qualitative analysis problem: given a POMDP with an omega-regular objective, whether there is an observation-based strategy to achieve the objective with probability 1 (almost-sure winning), or with positive probability (positive winning). Our main results are twofold. First, we present a complete picture of the computational complexity of the qualitative analysis of POMDPs with parity objectives (a canonical form to express omega-regular objectives) and its subclasses. Our contribution consists in establishing several upper and lower bounds that were not known in literature. Second, we present optimal bounds (matching upper and lower bounds) on the memory required by pure and randomized observation-based strategies for the qualitative analysis of POMDPs with parity objectives and its subclasses.},
author = {Chatterjee, Krishnendu and Doyen, Laurent and Henzinger, Thomas A},
issn = {2664-1690},
pages = {20},
publisher = {IST Austria},
title = {{Qualitative analysis of partially-observable Markov decision processes}},
doi = {10.15479/AT:IST-2009-0001},
year = {2009},
}
@article{599,
abstract = {The human CDK8 subcomplex (CDK8, cyclin C, Med12, and Med13) negatively regulates transcription in ways not completely defined; past studies suggested CDK8 kinase activity was required for its repressive function. Using a reconstituted transcription system together with recombinant or endogenous CDK8 subcomplexes, we demonstrate that, in fact, Med12 and Med13 are critical for subcomplex-dependent repression, whereas CDK8 kinase activity is not. A hallmark of activated transcription is efficient reinitiation from promoter-bound scaffold complexes that recruit a series of pol II enzymes to the gene. Notably, the CDK8 submodule strongly represses even reinitiation events, suggesting a means to fine tune transcript levels. Structural and biochemical studies confirm the CDK8 submodule binds the Mediator leg/tail domain via the Med13 subunit, and this submodule-Mediator association precludes pol II recruitment. Collectively, these results reveal the CDK8 subcomplex functions as a simple switch that controls the Mediator-pol II interaction to help regulate transcription initiation and reinitiation events. As Mediator is generally required for expression of protein-coding genes, this may reflect a common mechanism by which activated transcription is shut down in human cells.},
author = {Knuesel, Matthew and Meyer, Krista and Bernecky, Carrie A and Taatjes, Dylan},
journal = {Genes and Development},
number = {4},
pages = {439 -- 451},
publisher = {Cold Spring Harbor Laboratory Press},
title = {{The human CDK8 subcomplex is a molecular switch that controls Mediator coactivator function}},
doi = {10.1101/gad.1767009},
volume = {23},
year = {2009},
}
@inbook{164,
abstract = {Let g be a cubic polynomial with integer coefficients and n>9 variables, and assume that the congruence g=0 modulo p^k is soluble for all prime powers p^k. We show that the equation g=0 has infinitely many integer solutions when the cubic part of g defines a projective hypersurface with singular locus of dimension <n-10. The proof is based on the Hardy-Littlewood circle method.},
author = {Browning, Timothy D and Heath Brown, Roger},
booktitle = {Analytic Number Theory: Essays in honour of Klaus Roth},
pages = {75 -- 90},
publisher = {Cambridge University Press},
title = {{Integral points on cubic hypersurfaces}},
year = {2009},
}
@article{1038,
abstract = {One possible way to produce ultra-cold, high-phase-space-density quantum gases of molecules in the rovibronic ground state is given by molecule association from quantum-degenerate atomic gases on a Feshbach resonance and subsequent coherent optical multi-photon transfer into the rovibronic ground state. In ultra-cold samples of Cs2 molecules, we observe two-photon dark resonances that connect the intermediate rovibrational level |v=73,J=2 with the rovibrational ground state |v=0,J=0 of the singlet X 1 ∑ g + ground-state potential. For precise dark resonance spectroscopy we exploit the fact that it is possible to efficiently populate the level |v=73,J=2 by two-photon transfer from the dissociation threshold with the stimulated Raman adiabatic passage (STIRAP) technique. We find that at least one of the two-photon resonances is sufficiently strong to allow future implementation of coherent STIRAP transfer of a molecular quantum gas to the rovibrational ground state |v=0,J=0.},
author = {Mark, Manfred and Danzl, Johann G and Haller, Elmar and Gustavsson, Mattias and Bouloufa, Nadia and Dulieu, Olivier and Salami, Houssam and Bergeman, Thomas and Ritsch, Helmut and Hart, Russell and Nägerl, Hanns},
journal = {Applied Physics B: Lasers and Optics},
number = {2},
pages = {219 -- 225},
publisher = {Springer},
title = {{Dark resonances for ground-state transfer of molecular quantum gases}},
doi = {10.1007/s00340-009-3407-1},
volume = {95},
year = {2009},
}
@article{1040,
abstract = {Ultracold atomic physics offers myriad possibilities to study strongly correlated many-body systems in lower dimensions. Typically, only ground-state phases are accessible. Using a tunable quantum gas of bosonic cesium atoms, we realized and controlled in one-dimensional geometry a highly excited quantum phase that is stabilized in the presence of attractive interactions by maintaining and strengthening quantum correlations across a confinement-induced resonance. We diagnosed the crossover from repulsive to attractive interactions in terms of the stiffness and energy of the system. Our results open up the experimental study of metastable, excited, many-body phases with strong correlations and their dynamical properties.},
author = {Haller, Elmar and Gustavsson, Mattias and Mark, Manfred and Danzl, Johann G and Hart, Russell and Pupillo, Guido and Nägerl, Hanns},
journal = {Science},
number = {5945},
pages = {1224 -- 1227},
publisher = {American Association for the Advancement of Science},
title = {{Realization of an excited, strongly correlated quantum gas Phase}},
doi = {10.1126/science.1175850},
volume = {325},
year = {2009},
}
@article{1041,
abstract = {We demonstrate efficient transfer of ultracold molecules into a deeply bound rovibrational level of the singlet ground state potential in the presence of an optical lattice. The overall molecule creation efficiency is 25%, and the transfer efficiency to the rovibrational level |v = 73, J = 2) is above 80%. We find that the molecules in |v = 73, J = 2) are trapped in the optical lattice, and that the lifetime in the lattice is limited by optical excitation by the lattice light. The molecule trapping time for a lattice depth of 15 atomic recoil energies is about 20 ms. We determine the trapping frequency by the lattice phase and amplitude modulation technique. It will now be possible to transfer the molecules to the rovibrational ground state |v = 0, J = 0) in the presence of the optical lattice.},
author = {Danzl, Johann G and Mark, Manfred and Haller, Elmar and Gustavsson, Mattias and Hart, Russell and Liem, Andreas and Zellmer, Holger and Nägerl, Hanns},
journal = {New Journal of Physics},
publisher = {IOP Publishing Ltd.},
title = {{Deeply bound ultracold molecules in an optical lattice}},
doi = {10.1088/1367-2630/11/5/055036},
volume = {11},
year = {2009},
}