@article{14658, abstract = {We investigate spin-charge separation of a spin- 1 2 Fermi system confined in a triple well where multiple bands are occupied. We assume that our finite fermionic system is close to fully spin polarized while being doped by a hole and an impurity fermion with opposite spin. Our setup involves ferromagnetic couplings among the particles in different bands, leading to the development of strong spin-transport correlations in an intermediate interaction regime. Interactions are then strong enough to lift the degeneracy among singlet and triplet spin configurations in the well of the spin impurity but not strong enough to prohibit hole-induced magnetic excitations to the singlet state. Despite the strong spin-hole correlations, the system exhibits spin-charge deconfinement allowing for long-range entanglement of the spatial and spin degrees of freedom.}, author = {Becker, J. M. and Koutentakis, Georgios and Schmelcher, P.}, issn = {2643-1564}, journal = {Physical Review Research}, number = {4}, publisher = {American Physical Society}, title = {{Spin-charge correlations in finite one-dimensional multiband Fermi systems}}, doi = {10.1103/PhysRevResearch.5.043039}, volume = {5}, year = {2023}, } @article{14650, abstract = {We study the out-of-equilibrium quantum dynamics of dipolar polarons, i.e., impurities immersed in a dipolar Bose-Einstein condensate, after a quench of the impurity-boson interaction. We show that the dipolar nature of the condensate and of the impurity results in anisotropic relaxation dynamics, in particular, anisotropic dressing of the polaron. More relevantly for cold-atom setups, quench dynamics is strongly affected by the interplay between dipolar anisotropy and trap geometry. Our findings pave the way for simulating impurities in anisotropic media utilizing experiments with dipolar mixtures.}, author = {Volosniev, Artem and Bighin, Giacomo and Santos, Luis and Peña Ardila, Luisllu A.}, issn = {2542-4653}, journal = {SciPost Physics}, keywords = {General Physics and Astronomy}, number = {6}, publisher = {SciPost Foundation}, title = {{Non-equilibrium dynamics of dipolar polarons}}, doi = {10.21468/scipostphys.15.6.232}, volume = {15}, year = {2023}, } @article{13278, abstract = {We present a numerical analysis of spin-1/2 fermions in a one-dimensional harmonic potential in the presence of a magnetic point-like impurity at the center of the trap. The model represents a few-body analogue of a magnetic impurity in the vicinity of an s-wave superconductor. Already for a few particles we find a ground-state level crossing between sectors with different fermion parities. We interpret this crossing as a few-body precursor of a quantum phase transition, which occurs when the impurity "breaks" a Cooper pair. This picture is further corroborated by analyzing density-density correlations in momentum space. Finally, we discuss how the system may be realized with existing cold-atoms platforms.}, author = {Rammelmüller, Lukas and Huber, David and Čufar, Matija and Brand, Joachim and Hammer, Hans-Werner and Volosniev, Artem}, issn = {2542-4653}, journal = {SciPost Physics}, keywords = {General Physics and Astronomy}, number = {1}, publisher = {SciPost Foundation}, title = {{Magnetic impurity in a one-dimensional few-fermion system}}, doi = {10.21468/scipostphys.14.1.006}, volume = {14}, year = {2023}, } @article{14246, abstract = {The model of a ring threaded by the Aharonov-Bohm flux underlies our understanding of a coupling between gauge potentials and matter. The typical formulation of the model is based upon a single particle picture, and should be extended when interactions with other particles become relevant. Here, we illustrate such an extension for a particle in an Aharonov-Bohm ring subject to interactions with a weakly interacting Bose gas. We show that the ground state of the system can be described using the Bose-polaron concept—a particle dressed by interactions with a bosonic environment. We connect the energy spectrum to the effective mass of the polaron, and demonstrate how to change currents in the system by tuning boson-particle interactions. Our results suggest the Aharonov-Bohm ring as a platform for studying coherence and few- to many-body crossover of quasi-particles that arise from an impurity immersed in a medium.}, author = {Brauneis, Fabian and Ghazaryan, Areg and Hammer, Hans-Werner and Volosniev, Artem}, issn = {2399-3650}, journal = {Communications Physics}, keywords = {General Physics and Astronomy}, publisher = {Springer Nature}, title = {{Emergence of a Bose polaron in a small ring threaded by the Aharonov-Bohm flux}}, doi = {10.1038/s42005-023-01281-2}, volume = {6}, year = {2023}, } @article{14238, abstract = {We demonstrate that a sodium dimer, Na2(13Σ+u), residing on the surface of a helium nanodroplet, can be set into rotation by a nonresonant 1.0 ps infrared laser pulse. The time-dependent degree of alignment measured, exhibits a periodic, gradually decreasing structure that deviates qualitatively from that expected for gas-phase dimers. Comparison to alignment dynamics calculated from the time-dependent rotational Schrödinger equation shows that the deviation is due to the alignment dependent interaction between the dimer and the droplet surface. This interaction confines the dimer to the tangential plane of the droplet surface at the point where it resides and is the reason that the observed alignment dynamics is also well described by a 2D quantum rotor model.}, author = {Kranabetter, Lorenz and Kristensen, Henrik H. and Ghazaryan, Areg and Schouder, Constant A. and Chatterley, Adam S. and Janssen, Paul and Jensen, Frank and Zillich, Robert E. and Lemeshko, Mikhail and Stapelfeldt, Henrik}, issn = {1079-7114}, journal = {Physical Review Letters}, number = {5}, publisher = {American Physical Society}, title = {{Nonadiabatic laser-induced alignment dynamics of molecules on a surface}}, doi = {10.1103/PhysRevLett.131.053201}, volume = {131}, year = {2023}, } @article{14756, abstract = {We prove the r-spin cobordism hypothesis in the setting of (weak) 2-categories for every positive integer r: the 2-groupoid of 2-dimensional fully extended r-spin TQFTs with given target is equivalent to the homotopy fixed points of an induced Spin 2r -action. In particular, such TQFTs are classified by fully dualisable objects together with a trivialisation of the rth power of their Serre automorphisms. For r=1, we recover the oriented case (on which our proof builds), while ordinary spin structures correspond to r=2. To construct examples, we explicitly describe Spin 2r​-homotopy fixed points in the equivariant completion of any symmetric monoidal 2-category. We also show that every object in a 2-category of Landau–Ginzburg models gives rise to fully extended spin TQFTs and that half of these do not factor through the oriented bordism 2-category.}, author = {Carqueville, Nils and Szegedy, Lorant}, issn = {1663-487X}, journal = {Quantum Topology}, keywords = {Geometry and Topology, Mathematical Physics}, number = {3}, pages = {467--532}, publisher = {European Mathematical Society}, title = {{Fully extended r-spin TQFTs}}, doi = {10.4171/qt/193}, volume = {14}, year = {2023}, } @article{10845, abstract = {We study an impurity with a resonance level whose position coincides with the Fermi energy of the surrounding Fermi gas. An impurity causes a rapid variation of the scattering phase shift for fermions at the Fermi surface, introducing a new characteristic length scale into the problem. We investigate manifestations of this length scale in the self-energy of the impurity and in the density of the bath. Our calculations reveal a model-independent deformation of the density of the Fermi gas, which is determined by the width of the resonance. To provide a broader picture, we investigate time evolution of the density in quench dynamics, and study the behavior of the system at finite temperatures. Finally, we briefly discuss implications of our findings for the Fermi-polaron problem.}, author = {Maslov, Mikhail and Lemeshko, Mikhail and Volosniev, Artem}, issn = {2643-1564}, journal = {Physical Review Research}, publisher = {American Physical Society}, title = {{Impurity with a resonance in the vicinity of the Fermi energy}}, doi = {10.1103/PhysRevResearch.4.013160}, volume = {4}, year = {2022}, } @article{10771, abstract = {A critical overview of the theory of the chirality-induced spin selectivity (CISS) effect, that is, phenomena in which the chirality of molecular species imparts significant spin selectivity to various electron processes, is provided. Based on discussions in a recently held workshop, and further work published since, the status of CISS effects—in electron transmission, electron transport, and chemical reactions—is reviewed. For each, a detailed discussion of the state-of-the-art in theoretical understanding is provided and remaining challenges and research opportunities are identified.}, author = {Evers, Ferdinand and Aharony, Amnon and Bar-Gill, Nir and Entin-Wohlman, Ora and Hedegård, Per and Hod, Oded and Jelinek, Pavel and Kamieniarz, Grzegorz and Lemeshko, Mikhail and Michaeli, Karen and Mujica, Vladimiro and Naaman, Ron and Paltiel, Yossi and Refaely-Abramson, Sivan and Tal, Oren and Thijssen, Jos and Thoss, Michael and Van Ruitenbeek, Jan M. and Venkataraman, Latha and Waldeck, David H. and Yan, Binghai and Kronik, Leeor}, issn = {15214095}, journal = {Advanced Materials}, number = {13}, publisher = {Wiley}, title = {{Theory of chirality induced spin selectivity: Progress and challenges}}, doi = {10.1002/adma.202106629}, volume = {34}, year = {2022}, } @article{11552, abstract = {Rotational dynamics of D2 molecules inside helium nanodroplets is induced by a moderately intense femtosecond pump pulse and measured as a function of time by recording the yield of HeD+ ions, created through strong-field dissociative ionization with a delayed femtosecond probe pulse. The yield oscillates with a period of 185 fs, reflecting field-free rotational wave packet dynamics, and the oscillation persists for more than 500 periods. Within the experimental uncertainty, the rotational constant BHe of the in-droplet D2 molecule, determined by Fourier analysis, is the same as Bgas for an isolated D2 molecule. Our observations show that the D2 molecules inside helium nanodroplets essentially rotate as free D2 molecules.}, author = {Qiang, Junjie and Zhou, Lianrong and Lu, Peifen and Lin, Kang and Ma, Yongzhe and Pan, Shengzhe and Lu, Chenxu and Jiang, Wenyu and Sun, Fenghao and Zhang, Wenbin and Li, Hui and Gong, Xiaochun and Averbukh, Ilya Sh and Prior, Yehiam and Schouder, Constant A. and Stapelfeldt, Henrik and Cherepanov, Igor and Lemeshko, Mikhail and Jäger, Wolfgang and Wu, Jian}, issn = {10797114}, journal = {Physical Review Letters}, number = {24}, publisher = {American Physical Society}, title = {{Femtosecond rotational dynamics of D2 molecules in superfluid helium nanodroplets}}, doi = {10.1103/PhysRevLett.128.243201}, volume = {128}, year = {2022}, } @article{11590, abstract = {We investigate the ground-state properties of weakly repulsive one-dimensional bosons in the presence of an attractive zero-range impurity potential. First, we derive mean-field solutions to the problem on a finite ring for the two asymptotic cases: (i) all bosons are bound to the impurity and (ii) all bosons are in a scattering state. Moreover, we derive the critical line that separates these regimes in the parameter space. In the thermodynamic limit, this critical line determines the maximum number of bosons that can be bound by the impurity potential, forming an artificial atom. Second, we validate the mean-field results using the flow equation approach and the multi-layer multi-configuration time-dependent Hartree method for atomic mixtures. While beyond-mean-field effects destroy long-range order in the Bose gas, the critical boson number is unaffected. Our findings are important for understanding such artificial atoms in low-density Bose gases with static and mobile impurities.}, author = {Brauneis, Fabian and Backert, Timothy G. and Mistakidis, Simeon I. and Lemeshko, Mikhail and Hammer, Hans Werner and Volosniev, Artem}, issn = {1367-2630}, journal = {New Journal of Physics}, number = {6}, publisher = {IOP Publishing}, title = {{Artificial atoms from cold bosons in one dimension}}, doi = {10.1088/1367-2630/ac78d8}, volume = {24}, year = {2022}, }