Publications by Department of Theory of Condensed Matter

Departments of ISQI | Publications of ISQI

2023
14.	Flavio Capotondi, Alexander Lichtenstein, Serguei Molodtsov, Leonard Mueller, Andre Philippi-Kobs, Przemysław Piekarz, Konrad J. Kapcia, Victor Tkachenko, Beata Ziaja Electronic processes occurring during ultrafast demagnetization of cobalt triggered by x-ray photons tuned to the Co $L_3$ resonance Phys. Rev. B, 107 , pp. 094402, 2023. Links \| BibTeX @article{PhysRevB.107.094402, title = {Electronic processes occurring during ultrafast demagnetization of cobalt triggered by x-ray photons tuned to the Co $L_3$ resonance}, author = {Flavio Capotondi and Alexander Lichtenstein and Serguei Molodtsov and Leonard Mueller and Andre Philippi-Kobs and Przemysław Piekarz and Konrad J. Kapcia and Victor Tkachenko and Beata Ziaja}, url = {https://link.aps.org/doi/10.1103/PhysRevB.107.094402}, doi = {10.1103/PhysRevB.107.094402}, year = {2023}, date = {2023-03-01}, journal = {Phys. Rev. B}, volume = {107}, pages = {094402}, publisher = {American Physical Society}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close https://link.aps.org/doi/10.1103/PhysRevB.107.094402 doi:10.1103/PhysRevB.107.094402 Close
13.	Jan Barański, Magaldena Barańska, Tomasz Zienkiewicz, Konrad J. Kapcia Quench dynamics of Fano-like resonances in the presence of the on-dot superconducting pairing Scientific Reports, 13 (1), pp. 7639, 2023, ISSN: 2045-2322. Abstract \| Links \| BibTeX @article{Baranski2023, title = {Quench dynamics of Fano-like resonances in the presence of the on-dot superconducting pairing}, author = {Jan Bara{ń}ski and Magaldena Bara{ń}ska and Tomasz Zienkiewicz and Konrad J. Kapcia}, url = {https://doi.org/10.1038/s41598-023-34376-5}, doi = {10.1038/s41598-023-34376-5}, issn = {2045-2322}, year = {2023}, date = {2023-01-01}, journal = {Scientific Reports}, volume = {13}, number = {1}, pages = {7639}, abstract = {We explore the electron dynamics of a system composed of double quantum dot embedded between metallic and superconducting leads in a “T-shape” geometry. In nanoscopic systems, where electron transfer between electrodes can be realized via different paths, interference effects play an important role. For double quantum dot system in the chosen geometry, interference of electrons transferred between electrodes via the interfacial quantum dot and electrons scattered on the side dot gives rise to Fano-like interference. If such a system is additionally coupled to a superconducting electrode, together with the well-understood Fano resonance an additional resonance appears on the opposite side of the Fermi level. In the recent work (Barański et al. in Sci Rep 10:2881, 2020), we showed that this resonance occurs solely as a result of the local pairing of non-scattered electrons with scattered ones. In this work, considering the quench dynamics, we explore how much time is required for formation of each of these resonances. In particular, (i) we analyze the charge oscillations between subsystems; (ii) we estimate the time required for each resonance to achieve stable equilibrium upon an abrupt change of interdot connection; (iii) we discuss a typical energy and time scales for experiments on similar architectures.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close We explore the electron dynamics of a system composed of double quantum dot embedded between metallic and superconducting leads in a “T-shape” geometry. In nanoscopic systems, where electron transfer between electrodes can be realized via different paths, interference effects play an important role. For double quantum dot system in the chosen geometry, interference of electrons transferred between electrodes via the interfacial quantum dot and electrons scattered on the side dot gives rise to Fano-like interference. If such a system is additionally coupled to a superconducting electrode, together with the well-understood Fano resonance an additional resonance appears on the opposite side of the Fermi level. In the recent work (Barański et al. in Sci Rep 10:2881, 2020), we showed that this resonance occurs solely as a result of the local pairing of non-scattered electrons with scattered ones. In this work, considering the quench dynamics, we explore how much time is required for formation of each of these resonances. In particular, (i) we analyze the charge oscillations between subsystems; (ii) we estimate the time required for each resonance to achieve stable equilibrium upon an abrupt change of interdot connection; (iii) we discuss a typical energy and time scales for experiments on similar architectures. Close https://doi.org/10.1038/s41598-023-34376-5 doi:10.1038/s41598-023-34376-5 Close
12.	Jakub Skórka, Konrad J. Kapcia, Paweł T. Jochym, Andrzej Ptok Chiral phonons in binary compounds ABi (A = K, Rb, Cs) with P21/c structure Materials Today Communications, 35 , pp. 105888, 2023, ISSN: 2352-4928. Abstract \| Links \| BibTeX @article{SKORKA2023105888, title = {Chiral phonons in binary compounds ABi (A = K, Rb, Cs) with P21/c structure}, author = {Jakub Skórka and Konrad J. Kapcia and Paweł T. Jochym and Andrzej Ptok}, url = {https://www.sciencedirect.com/science/article/pii/S2352492823005792}, doi = {https://doi.org/10.1016/j.mtcomm.2023.105888}, issn = {2352-4928}, year = {2023}, date = {2023-01-01}, journal = {Materials Today Communications}, volume = {35}, pages = {105888}, abstract = {Binary compounds ABi (A = K, Rb, Cs) crystallize in P21/c structure containing both clockwise and anticlockwise chiral chains of Bi atoms. Electronic band structure exhibits the insulating nature of these systems, with the band gap about 0.25eV. The presented study of dynamical properties confirm a stability of the system with P21/c symmetry. The crystal structure contains the quasi-one-dimensional Bi chains, exhibiting four-fold-like rotational “local” symmetry. Nevertheless, the system formally possesses two-fold rotational symmetry. Independently of the absence of the three-fold (or higher) rotational symmetry axes for the whole crystal, the chiral modes propagate along the Bi atom chains in these systems. We discuss basic properties of these modes in monoatomic chiral chains. We show that the two-fold rotational symmetry axis affects the main properties of the chiral phonons, which are not realized at the high-symmetry points, but along some paths between them in the reciprocal space. In addition, in the doped system, the chiral phonons possess non-zero total angular momentum.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Binary compounds ABi (A = K, Rb, Cs) crystallize in P21/c structure containing both clockwise and anticlockwise chiral chains of Bi atoms. Electronic band structure exhibits the insulating nature of these systems, with the band gap about 0.25eV. The presented study of dynamical properties confirm a stability of the system with P21/c symmetry. The crystal structure contains the quasi-one-dimensional Bi chains, exhibiting four-fold-like rotational “local” symmetry. Nevertheless, the system formally possesses two-fold rotational symmetry. Independently of the absence of the three-fold (or higher) rotational symmetry axes for the whole crystal, the chiral modes propagate along the Bi atom chains in these systems. We discuss basic properties of these modes in monoatomic chiral chains. We show that the two-fold rotational symmetry axis affects the main properties of the chiral phonons, which are not realized at the high-symmetry points, but along some paths between them in the reciprocal space. In addition, in the doped system, the chiral phonons possess non-zero total angular momentum. Close https://www.sciencedirect.com/science/article/pii/S2352492823005792 doi:https://doi.org/10.1016/j.mtcomm.2023.105888 Close
11.	Jan Barański, Konrad J. Kapcia Dynamics of Fano-Like Resonances in Double-Quantum-Dot Systems Acta Physica Polonica A, 143 (2), pp. 143, 2023. Abstract \| Links \| BibTeX @article{Jan_Baranski2023-id, title = {Dynamics of Fano-Like Resonances in Double-Quantum-Dot Systems}, author = {Jan Barański and Konrad J. Kapcia}, url = {http://appol.ifpan.edu.pl/index.php/appa/article/view/143_143}, year = {2023}, date = {2023-01-01}, journal = {Acta Physica Polonica A}, volume = {143}, number = {2}, pages = {143}, abstract = {Quantum interference effects appearing in mesoscopic heterostructures have been extensively studied in static conditions over the last decades. It is interesting to examine the dynamics of these phenomena and get insight into the process of the formation of interference patterns. In this work, we analyze the time required for the formation of Fano-like resonances in a double quantum dot system. We examined the time evolution of conductance upon establishing an abrupt connection between quantum dots. Asymmetric Fano lines are characterized by the close coexistence of resonant enhancement and resonant suppression. Therefore, we pay particular attention to voltages, which in the static case, correspond to both these features. Our research shows that the analyzed resonances are characterized by two time scales: (i) the first one related to charge oscillations between subsystems and mostly governed by the interdot coupling constant and the relative position of energy levels of quantum dots, and (ii) the second one associated to the electron scattering on a continuum of states and responsible for the relaxation. We also show that the time required for achieving a static solution is different for voltages corresponding to local minima and local maxima.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Quantum interference effects appearing in mesoscopic heterostructures have been extensively studied in static conditions over the last decades. It is interesting to examine the dynamics of these phenomena and get insight into the process of the formation of interference patterns. In this work, we analyze the time required for the formation of Fano-like resonances in a double quantum dot system. We examined the time evolution of conductance upon establishing an abrupt connection between quantum dots. Asymmetric Fano lines are characterized by the close coexistence of resonant enhancement and resonant suppression. Therefore, we pay particular attention to voltages, which in the static case, correspond to both these features. Our research shows that the analyzed resonances are characterized by two time scales: (i) the first one related to charge oscillations between subsystems and mostly governed by the interdot coupling constant and the relative position of energy levels of quantum dots, and (ii) the second one associated to the electron scattering on a continuum of states and responsible for the relaxation. We also show that the time required for achieving a static solution is different for voltages corresponding to local minima and local maxima. Close http://appol.ifpan.edu.pl/index.php/appa/article/view/143_143 Close
2022
10.	Tymoteusz Salamon, Bernhard Irsigler, Debraj Rakshit, Maciej Lewenstein, Tobias Grass, Ravindra W. Chhajlany Flat-band-induced superconductivity in synthetic bilayer optical lattices Phys. Rev. B, 106 , pp. 174503, 2022. Abstract \| Links \| BibTeX @article{PhysRevB.106.174503, title = {Flat-band-induced superconductivity in synthetic bilayer optical lattices}, author = {Tymoteusz Salamon and Bernhard Irsigler and Debraj Rakshit and Maciej Lewenstein and Tobias Grass and Ravindra W. Chhajlany}, url = {https://link.aps.org/doi/10.1103/PhysRevB.106.174503}, doi = {10.1103/PhysRevB.106.174503}, year = {2022}, date = {2022-11-04}, journal = {Phys. Rev. B}, volume = {106}, pages = {174503}, publisher = {American Physical Society}, abstract = {Stacking two layers of graphene with a relative twist angle gives rise to Moiré patterns, which can strongly modify electronic behavior and may lead to unconventional superconductivity. A synthetic version of twisted bilayers can be engineered with cold atoms in optical lattices. Here, the bilayer structure is mimicked through coupling between atomic sublevels, and the twist is achieved by a spatial modulation of this coupling. In the present paper, we investigate the superconducting behavior of fermionic atoms in such a synthetic twisted bilayer lattice. Attractive interactions between the atoms are treated on the mean-field level, and the superconducting behavior is analyzed via the self-consistently determined pairing gap. A strong enhancement of the pairing gap is found when a quasi-flat band structure occurs at the Fermi surface, reflecting the prominent role played by the twist on the superconductivity. The tunability of interactions allows for the switching of superconducting correlations from intra (synthetic) layer to inter (synthetic) layer. This includes also the intermediate scenario, in which the competition between inter- and intra-layer coupling completely destroys the superconducting behavior, resulting in re-entrant superconductivity upon tuning of the interactions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Stacking two layers of graphene with a relative twist angle gives rise to Moiré patterns, which can strongly modify electronic behavior and may lead to unconventional superconductivity. A synthetic version of twisted bilayers can be engineered with cold atoms in optical lattices. Here, the bilayer structure is mimicked through coupling between atomic sublevels, and the twist is achieved by a spatial modulation of this coupling. In the present paper, we investigate the superconducting behavior of fermionic atoms in such a synthetic twisted bilayer lattice. Attractive interactions between the atoms are treated on the mean-field level, and the superconducting behavior is analyzed via the self-consistently determined pairing gap. A strong enhancement of the pairing gap is found when a quasi-flat band structure occurs at the Fermi surface, reflecting the prominent role played by the twist on the superconductivity. The tunability of interactions allows for the switching of superconducting correlations from intra (synthetic) layer to inter (synthetic) layer. This includes also the intermediate scenario, in which the competition between inter- and intra-layer coupling completely destroys the superconducting behavior, resulting in re-entrant superconductivity upon tuning of the interactions. Close https://link.aps.org/doi/10.1103/PhysRevB.106.174503 doi:10.1103/PhysRevB.106.174503 Close
9.	Maciej Lewenstein, David Cirauqui, Miguel Angel Garcia-March, Guillem Guigo i Corominas, Przemysław R. Grzybowski, Jose Saavedra, Martin Wilkens, Jan Wehr Haake-Lewenstein-Wilkens approach to spin-glasses revisited Journal of Physics A: Mathematical and Theoretical, 2022. Abstract \| Links \| BibTeX @article{10.1088/1751-8121/ac9d10b, title = {Haake-Lewenstein-Wilkens approach to spin-glasses revisited}, author = {Maciej Lewenstein and David Cirauqui and Miguel Angel Garcia-March and Guillem Guigo i Corominas and Przemysław R. Grzybowski and Jose Saavedra and Martin Wilkens and Jan Wehr}, url = {http://iopscience.iop.org/article/10.1088/1751-8121/ac9d10}, year = {2022}, date = {2022-10-24}, journal = {Journal of Physics A: Mathematical and Theoretical}, abstract = {We revisit the Haake-Lewenstein-Wilkens (HLW) approach to Edwards-Anderson (EA) model of Ising spin glass [Phys. Rev. Lett. 55, 2606 (1985)]. This approach consists in evaluation and analysis of the probability distribution of conﬁgurations of two replicas of the system, averaged over quenched disorder. This probability This approximate result suggest that qEA > 0 at 0 < T < Tc in 3D and 4D. The case of 2D seems to be a little more subtle, since in the present approach energy increase for a domain wall competes with boundary/edge effects more strongly in 2D; still our approach predicts spin glass order at sufﬁciently low temperature. We speculate, how these predictions conﬁrm/contradict widely spread opinions that: i) There exist only one (up to the spin ﬂip) ground state in EA model in 2D, 3D and 4D; ii) There is (no) spin glass transition in 3D and 4D (2D). This paper is dedicated to the memories of Fritz Haake and Marek Cieplak.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close We revisit the Haake-Lewenstein-Wilkens (HLW) approach to Edwards-Anderson (EA) model of Ising spin glass [Phys. Rev. Lett. 55, 2606 (1985)]. This approach consists in evaluation and analysis of the probability distribution of conﬁgurations of two replicas of the system, averaged over quenched disorder. This probability This approximate result suggest that qEA > 0 at 0 < T < Tc in 3D and 4D. The case of 2D seems to be a little more subtle, since in the present approach energy increase for a domain wall competes with boundary/edge effects more strongly in 2D; still our approach predicts spin glass order at sufﬁciently low temperature. We speculate, how these predictions conﬁrm/contradict widely spread opinions that: i) There exist only one (up to the spin ﬂip) ground state in EA model in 2D, 3D and 4D; ii) There is (no) spin glass transition in 3D and 4D (2D). This paper is dedicated to the memories of Fritz Haake and Marek Cieplak. Close http://iopscience.iop.org/article/10.1088/1751-8121/ac9d10 Close
8.	Shilan Abo, Grzegorz Chimczak, Anna Kowalewska-Kudłaszyk, Jan Peřina Jr, Ravindra W. Chhajlany, Adam Miranowicz Hybrid photon–phonon blockade Scientific Reports, 12 , pp. 17655, 2022, ISSN: 2045-2322. Abstract \| Links \| BibTeX @article{shilan2022, title = {Hybrid photon–phonon blockade}, author = {Shilan Abo and Grzegorz Chimczak and Anna Kowalewska-Kudłaszyk and Jan Peřina Jr and Ravindra W. Chhajlany and Adam Miranowicz }, url = {https://www.nature.com/articles/s41598-022-21267-4}, doi = {https://doi.org/10.1038/s41598-022-21267-4}, issn = {2045-2322}, year = {2022}, date = {2022-10-21}, journal = {Scientific Reports}, volume = {12}, pages = {17655}, abstract = {We describe a novel type of blockade in a hybrid mode generated by linear coupling of photonic and phononic modes. We refer to this effect as hybrid photon–phonon blockade and show how it can be generated and detected in a driven nonlinear optomechanical superconducting system. Thus, we study boson-number correlations in the photon, phonon, and hybrid modes in linearly coupled microwave and mechanical resonators with a superconducting qubit inserted in one of them. We find such system parameters for which we observe eight types of different combinations of either blockade or tunnelling effects (defined via the sub- and super-Poissonian statistics, respectively) for photons, phonons, and hybrid bosons. In particular, we find that the hybrid photon–phonon blockade can be generated by mixing the photonic and phononic modes which do not exhibit blockade.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close We describe a novel type of blockade in a hybrid mode generated by linear coupling of photonic and phononic modes. We refer to this effect as hybrid photon–phonon blockade and show how it can be generated and detected in a driven nonlinear optomechanical superconducting system. Thus, we study boson-number correlations in the photon, phonon, and hybrid modes in linearly coupled microwave and mechanical resonators with a superconducting qubit inserted in one of them. We find such system parameters for which we observe eight types of different combinations of either blockade or tunnelling effects (defined via the sub- and super-Poissonian statistics, respectively) for photons, phonons, and hybrid bosons. In particular, we find that the hybrid photon–phonon blockade can be generated by mixing the photonic and phononic modes which do not exhibit blockade. Close https://www.nature.com/articles/s41598-022-21267-4 doi:https://doi.org/10.1038/s41598-022-21267-4 Close
7.	Konrad J. Kapcia, V. Tkachenko, F. Capotondi, A. Lichtenstein, S. Molodtsov, L. Müller, A. Philippi-Kobs, P. Piekarz, B. Ziaja Modeling of ultrafast X-ray induced magnetization dynamics in magnetic multilayer systems npj Computational Materials, 8 , pp. 212, 2022. Abstract \| Links \| BibTeX @article{Kapcia2022, title = {Modeling of ultrafast X-ray induced magnetization dynamics in magnetic multilayer systems}, author = {Konrad J. Kapcia and V. Tkachenko and F. Capotondi and A. Lichtenstein and S. Molodtsov and L. Müller and A. Philippi-Kobs and P. Piekarz and B. Ziaja}, url = {https://www.nature.com/articles/s41524-022-00895-4}, doi = {10.1038/s41524-022-00895-4}, year = {2022}, date = {2022-10-01}, journal = {npj Computational Materials}, volume = {8}, pages = {212}, abstract = {In this work, we report on modeling results obtained with our recently developed simulation tool enabling nanoscopic description of electronic processes in X-ray irradiated ferromagnetic materials. With this tool, we have studied the response of Co/Pt multilayer system irradiated by an ultrafast extreme ultraviolet pulse at the M-edge of Co (photon energy ~60 eV). It was previously investigated experimentally at the FERMI free-electron-laser facility, using the magnetic small-angle X-ray scattering technique. Our simulations show that the magnetic scattering signal from cobalt decreases on femtosecond timescales due to electronic excitation, relaxation, and transport processes both in the cobalt and in the platinum layers, following the trend observed in the experimental data. The confirmation of the predominant role of electronic processes for X-ray induced demagnetization in the regime below the structural damage threshold is a step toward quantitative control and manipulation of X-ray induced magnetic processes on femtosecond timescales.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close In this work, we report on modeling results obtained with our recently developed simulation tool enabling nanoscopic description of electronic processes in X-ray irradiated ferromagnetic materials. With this tool, we have studied the response of Co/Pt multilayer system irradiated by an ultrafast extreme ultraviolet pulse at the M-edge of Co (photon energy ~60 eV). It was previously investigated experimentally at the FERMI free-electron-laser facility, using the magnetic small-angle X-ray scattering technique. Our simulations show that the magnetic scattering signal from cobalt decreases on femtosecond timescales due to electronic excitation, relaxation, and transport processes both in the cobalt and in the platinum layers, following the trend observed in the experimental data. The confirmation of the predominant role of electronic processes for X-ray induced demagnetization in the regime below the structural damage threshold is a step toward quantitative control and manipulation of X-ray induced magnetic processes on femtosecond timescales. Close https://www.nature.com/articles/s41524-022-00895-4 doi:10.1038/s41524-022-00895-4 Close
6.	Miłosz Rybak, Tomasz Woźniak, Magdalena Birowska, Filip Dybała, Alfredo Segura, Konrad J. Kapcia, Paweł Scharoch, Robert Kudrawiec Stress-Tuned Optical Transitions in Layered 1T-MX2 (M=Hf, Zr, Sn; X=S, Se) Crystals Nanomaterials, 12 (19), pp. 3433, 2022. Abstract \| Links \| BibTeX @article{Rybak2022, title = {Stress-Tuned Optical Transitions in Layered 1T-MX2 (M=Hf, Zr, Sn; X=S, Se) Crystals }, author = {Miłosz Rybak and Tomasz Woźniak and Magdalena Birowska and Filip Dybała and Alfredo Segura and Konrad J. Kapcia and Paweł Scharoch and Robert Kudrawiec}, url = {https://www.mdpi.com/2079-4991/12/19/3433}, doi = {10.3390/nano12193433}, year = {2022}, date = {2022-09-30}, journal = {Nanomaterials}, volume = {12}, number = {19}, pages = {3433}, abstract = {Optical measurements under externally applied stresses allow us to study the materials’ electronic structure by comparing the pressure evolution of optical peaks obtained from experiments and theoretical calculations. We examine the stress-induced changes in electronic structure for the thermodynamically stable 1T polytype of selected MX2 compounds (M=Hf, Zr, Sn; X=S, Se), using the density functional theory. We demonstrate that considered 1T-MX2 materials are semiconducting with indirect character of the band gap, irrespective to the employed pressure as predicted using modified Becke–Johnson potential. We determine energies of direct interband transitions between bands extrema and in band-nesting regions close to Fermi level. Generally, the studied transitions are optically active, exhibiting in-plane polarization of light. Finally, we quantify their energy trends under external hydrostatic, uniaxial, and biaxial stresses by determining the linear pressure coefficients. Generally, negative pressure coefficients are obtained implying the narrowing of the band gap. The semiconducting-to-metal transition are predicted under hydrostatic pressure. We discuss these trends in terms of orbital composition of involved electronic bands. In addition, we demonstrate that the measured pressure coefficients of HfS2 and HfSe2 absorption edges are in perfect agreement with our predictions. Comprehensive and easy-to-interpret tables containing the optical features are provided to form the basis for assignation of optical peaks in future measurements.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Optical measurements under externally applied stresses allow us to study the materials’ electronic structure by comparing the pressure evolution of optical peaks obtained from experiments and theoretical calculations. We examine the stress-induced changes in electronic structure for the thermodynamically stable 1T polytype of selected MX2 compounds (M=Hf, Zr, Sn; X=S, Se), using the density functional theory. We demonstrate that considered 1T-MX2 materials are semiconducting with indirect character of the band gap, irrespective to the employed pressure as predicted using modified Becke–Johnson potential. We determine energies of direct interband transitions between bands extrema and in band-nesting regions close to Fermi level. Generally, the studied transitions are optically active, exhibiting in-plane polarization of light. Finally, we quantify their energy trends under external hydrostatic, uniaxial, and biaxial stresses by determining the linear pressure coefficients. Generally, negative pressure coefficients are obtained implying the narrowing of the band gap. The semiconducting-to-metal transition are predicted under hydrostatic pressure. We discuss these trends in terms of orbital composition of involved electronic bands. In addition, we demonstrate that the measured pressure coefficients of HfS2 and HfSe2 absorption edges are in perfect agreement with our predictions. Comprehensive and easy-to-interpret tables containing the optical features are provided to form the basis for assignation of optical peaks in future measurements. Close https://www.mdpi.com/2079-4991/12/19/3433 doi:10.3390/nano12193433 Close
5.	C. Lagoin, U. Bhattacharya, T. Grass, Ravindra W. Chhajlany, T. Salamon, K. Baldwin, L. Pfeiffer, M. Lewenstein, M. Holzmann, F. Dubin Extended Bose–Hubbard model with dipolar excitons Nature, 609 , pp. 485–489, 2022. Abstract \| Links \| BibTeX @article{Lagoin2022, title = {Extended Bose–Hubbard model with dipolar excitons}, author = {C. Lagoin and U. Bhattacharya and T. Grass and Ravindra W. Chhajlany and T. Salamon and K. Baldwin and L. Pfeiffer and M. Lewenstein and M. Holzmann and F. Dubin}, url = {https://www.nature.com/articles/s41586-022-05123-z}, doi = {10.1038/s41586-022-05123-z}, year = {2022}, date = {2022-09-14}, journal = {Nature}, volume = {609}, pages = {485–489}, abstract = {The Hubbard model constitutes one of the most celebrated theoretical frameworks of condensed-matter physics. It describes strongly correlated phases of interacting quantum particles confined in lattice potentials. For bosons, the Hubbard Hamiltonian has been deeply scrutinized for short-range on-site interactions. However, accessing longer-range couplings has remained elusive experimentally. This marks the frontier towards the extended Bose–Hubbard Hamiltonian, which enables insulating ordered phases at fractional lattice fillings. Here we implement this Hamiltonian by confining semiconductor dipolar excitons in an artificial two-dimensional square lattice. Strong dipolar repulsions between nearest-neighbour lattice sites then stabilize an insulating state at half filling. This characteristic feature of the extended Bose–Hubbard model exhibits the signatures theoretically expected for a chequerboard spatial order. Our work thus highlights that dipolar excitons enable controlled implementations of boson-like arrays with strong off-site interactions, in lattices with programmable geometries and more than 100 sites.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close The Hubbard model constitutes one of the most celebrated theoretical frameworks of condensed-matter physics. It describes strongly correlated phases of interacting quantum particles confined in lattice potentials. For bosons, the Hubbard Hamiltonian has been deeply scrutinized for short-range on-site interactions. However, accessing longer-range couplings has remained elusive experimentally. This marks the frontier towards the extended Bose–Hubbard Hamiltonian, which enables insulating ordered phases at fractional lattice fillings. Here we implement this Hamiltonian by confining semiconductor dipolar excitons in an artificial two-dimensional square lattice. Strong dipolar repulsions between nearest-neighbour lattice sites then stabilize an insulating state at half filling. This characteristic feature of the extended Bose–Hubbard model exhibits the signatures theoretically expected for a chequerboard spatial order. Our work thus highlights that dipolar excitons enable controlled implementations of boson-like arrays with strong off-site interactions, in lattices with programmable geometries and more than 100 sites. Close https://www.nature.com/articles/s41586-022-05123-z doi:10.1038/s41586-022-05123-z Close
4.	Przemysław Chełminiak Non-linear diffusion with stochastic resetting Journal of Physics A: Mathematical and Theoretical, 55 (38), pp. 384004, 2022. Abstract \| Links \| BibTeX @article{Che_miniak_2022, title = {Non-linear diffusion with stochastic resetting}, author = {Przemysław Chełminiak}, url = {https://doi.org/10.1088/1751-8121/ac870a}, doi = {10.1088/1751-8121/ac870a}, year = {2022}, date = {2022-08-01}, journal = {Journal of Physics A: Mathematical and Theoretical}, volume = {55}, number = {38}, pages = {384004}, publisher = {IOP Publishing}, abstract = {Resetting or restart, when applied to a stochastic process, usually brings its dynamics to a time-independent stationary state. In turn, the optimal resetting rate makes the mean time to reach a target to be finite and the shortest one. These and other innovative problems have been intensively studied over the last decade mainly in the case of ordinary diffusive processes. Intrigued by this fact we consider here the influence of stochastic resetting on the non-linear diffusion analysing its fundamental properties. We derive the exact formula for the mean squared displacement and demonstrate how it attains the steady-state value under the influence of the exponential resetting. This mechanism brings also about that the spatial support of the probability density function, which for the free non-linear diffusion is confined to the domain of a finite size, tends to span the entire set of real numbers. In addition, the first-passage properties for the non-linear diffusion intermittent by the exponential resetting are investigated. We find analytical expressions for the mean first-passage time and determine by means of the numerical method the optimal resetting rate which minimizes the mean time needed for a particle to reach a pre-determined target. Finally, we test and confirm the universal property that the relative fluctuation in the mean first-passage time of optimally restarted non-linear diffusion is equal to unity.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Resetting or restart, when applied to a stochastic process, usually brings its dynamics to a time-independent stationary state. In turn, the optimal resetting rate makes the mean time to reach a target to be finite and the shortest one. These and other innovative problems have been intensively studied over the last decade mainly in the case of ordinary diffusive processes. Intrigued by this fact we consider here the influence of stochastic resetting on the non-linear diffusion analysing its fundamental properties. We derive the exact formula for the mean squared displacement and demonstrate how it attains the steady-state value under the influence of the exponential resetting. This mechanism brings also about that the spatial support of the probability density function, which for the free non-linear diffusion is confined to the domain of a finite size, tends to span the entire set of real numbers. In addition, the first-passage properties for the non-linear diffusion intermittent by the exponential resetting are investigated. We find analytical expressions for the mean first-passage time and determine by means of the numerical method the optimal resetting rate which minimizes the mean time needed for a particle to reach a pre-determined target. Finally, we test and confirm the universal property that the relative fluctuation in the mean first-passage time of optimally restarted non-linear diffusion is equal to unity. Close https://doi.org/10.1088/1751-8121/ac870a doi:10.1088/1751-8121/ac870a Close
3.	Agnieszka Cichy, Konrad J. Kapcia, Andrzej Ptok Connection between the semiconductor-superconductor transition and the spin-polarized superconducting phase in the honeycomb lattice Phys. Rev. B, 105 , pp. 214510, 2022. Abstract \| Links \| BibTeX @article{Cichy2022, title = {Connection between the semiconductor-superconductor transition and the spin-polarized superconducting phase in the honeycomb lattice}, author = {Agnieszka Cichy and Konrad J. Kapcia and Andrzej Ptok}, url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.105.214510}, doi = {10.1103/PhysRevB.105.214510}, year = {2022}, date = {2022-06-14}, journal = {Phys. Rev. B}, volume = {105}, pages = {214510}, abstract = {The band structure of noninteracting fermions in the honeycomb lattice exhibits the Dirac cones at the corners of the Brillouin zone. As a consequence, fermions in this lattice manifest a semiconducting behavior below some critical value of the on-site attraction Uc. However, above Uc, the superconducting phase can occur. We discuss an interplay between the semiconductor-superconductor transition and the possibility of realization of the spin-polarized superconductivity (the so-called Sarma phase). We show that the critical interaction can be tuned by the next-nearest-neighbor (NNN) hopping in the absence of the magnetic field. Moreover, a critical value of the NNN hopping exists, defining a range of parameters for which the semiconducting phase can emerge. In the weak-coupling limit case, this quantum phase transition occurs for the absolute value of the NNN hopping equal to one third of the hopping between the nearest neighbors. Similarly, in the presence of the magnetic field, the Sarma phase can appear but only in a range of parameters for which initially the semiconducting state is observed. Both of these aspects are attributed to the Lifshitz transition, which is induced by the NNN hopping as well as the external magnetic field.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close The band structure of noninteracting fermions in the honeycomb lattice exhibits the Dirac cones at the corners of the Brillouin zone. As a consequence, fermions in this lattice manifest a semiconducting behavior below some critical value of the on-site attraction Uc. However, above Uc, the superconducting phase can occur. We discuss an interplay between the semiconductor-superconductor transition and the possibility of realization of the spin-polarized superconductivity (the so-called Sarma phase). We show that the critical interaction can be tuned by the next-nearest-neighbor (NNN) hopping in the absence of the magnetic field. Moreover, a critical value of the NNN hopping exists, defining a range of parameters for which the semiconducting phase can emerge. In the weak-coupling limit case, this quantum phase transition occurs for the absolute value of the NNN hopping equal to one third of the hopping between the nearest neighbors. Similarly, in the presence of the magnetic field, the Sarma phase can appear but only in a range of parameters for which initially the semiconducting state is observed. Both of these aspects are attributed to the Lifshitz transition, which is induced by the NNN hopping as well as the external magnetic field. Close https://journals.aps.org/prb/abstract/10.1103/PhysRevB.105.214510 doi:10.1103/PhysRevB.105.214510 Close
2.	Ichiro Inoue, Victor Tkachenko, Konrad J. Kapcia, Vladimir Lipp, Beata Ziaja, Yuichi Inubushi, Toru Hara, Makina Yabashi, Eiji Nishibori Delayed Onset and Directionality of X-Ray-Induced Atomic Displacements Observed on Subatomic Length Scales Phys. Rev. Lett., 128 , pp. 223203, 2022. Abstract \| Links \| BibTeX @article{Inoue2022, title = {Delayed Onset and Directionality of X-Ray-Induced Atomic Displacements Observed on Subatomic Length Scales}, author = {Ichiro Inoue and Victor Tkachenko and Konrad J. Kapcia and Vladimir Lipp and Beata Ziaja and Yuichi Inubushi and Toru Hara and Makina Yabashi and Eiji Nishibori}, url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.223203}, doi = {10.1103/PhysRevLett.128.223203}, year = {2022}, date = {2022-06-01}, journal = {Phys. Rev. Lett.}, volume = {128}, pages = {223203}, abstract = {Transient structural changes of Al2O3 on subatomic length scales following irradiation with an intense x-ray laser pulse (photon energy: 8.70 keV; pulse duration: 6 fs; fluence: 8×102 J/cm2) have been investigated by using an x-ray pump x-ray probe technique. The measurement reveals that aluminum and oxygen atoms remain in their original positions by ∼20 fs after the intensity maximum of the pump pulse, followed by directional atomic displacements at the fixed unit cell parameters. By comparing the experimental results and theoretical simulations, we interpret that electron excitation and relaxation triggered by the pump pulse modify the potential energy surface and drives the directional atomic displacements. Our results indicate that high-resolution x-ray structural analysis with the accuracy of 0.01 Å is feasible even with intense x-ray pulses by making the pulse duration shorter than the timescale needed to complete electron excitation and relaxation processes, which usually take up to a few tens of femtoseconds.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close Transient structural changes of Al2O3 on subatomic length scales following irradiation with an intense x-ray laser pulse (photon energy: 8.70 keV; pulse duration: 6 fs; fluence: 8×102 J/cm2) have been investigated by using an x-ray pump x-ray probe technique. The measurement reveals that aluminum and oxygen atoms remain in their original positions by ∼20 fs after the intensity maximum of the pump pulse, followed by directional atomic displacements at the fixed unit cell parameters. By comparing the experimental results and theoretical simulations, we interpret that electron excitation and relaxation triggered by the pump pulse modify the potential energy surface and drives the directional atomic displacements. Our results indicate that high-resolution x-ray structural analysis with the accuracy of 0.01 Å is feasible even with intense x-ray pulses by making the pulse duration shorter than the timescale needed to complete electron excitation and relaxation processes, which usually take up to a few tens of femtoseconds. Close https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.223203 doi:10.1103/PhysRevLett.128.223203 Close
2021
1.	Monika Aidelsburger, Luca Barbiero, Alejandro Bermudez, Titas Chanda, Alexandre Dauphin, Daniel González-Cuadra, Przemysław R. Grzybowski, Simon Hands, Fred Jendrzejewski, Johannes Jünemann adn Gediminas Juzeliu ̄nas, Valentin Kasper, Angelo Piga, Shi-Ju Ran, Matteo Rizzi, Germán Sierra, Luca Tagliacozzo, Emanuele Tirrito, Torsten V. Zache, Jakub Zakrzewski, Erez Zohar, Maciej Lewenstein Cold atoms meet lattice gauge theory Philos. Trans. A Math. Phys. Eng. Sci., 380 (2216), pp. 20210064, 2021. Abstract \| Links \| BibTeX @article{Aidelsburger2022-be, title = {Cold atoms meet lattice gauge theory}, author = {Monika Aidelsburger and Luca Barbiero and Alejandro Bermudez and Titas Chanda and Alexandre Dauphin and Daniel González-Cuadra and Przemysław R. Grzybowski and Simon Hands and Fred Jendrzejewski and Johannes Jünemann adn Gediminas Juzeliu ̄nas and Valentin Kasper and Angelo Piga and Shi-Ju Ran and Matteo Rizzi and Germán Sierra and Luca Tagliacozzo and Emanuele Tirrito and Torsten V. Zache and Jakub Zakrzewski and Erez Zohar and Maciej Lewenstein}, url = {https://royalsocietypublishing.org/doi/10.1098/rsta.2021.0064}, doi = {10.1098/rsta.2021.0064}, year = {2021}, date = {2021-12-20}, journal = {Philos. Trans. A Math. Phys. Eng. Sci.}, volume = {380}, number = {2216}, pages = {20210064}, publisher = {The Royal Society}, abstract = {The central idea of this review is to consider quantum field theory models relevant for particle physics and replace the fermionic matter in these models by a bosonic one. This is mostly motivated by the fact that bosons are more áccessible' and easier to manipulate for experimentalists, but this 'substitution' also leads to new physics and novel phenomena. It allows us to gain new information about among other things confinement and the dynamics of the deconfinement transition. We will thus consider bosons in dynamical lattices corresponding to the bosonic Schwinger or [Formula: see text] Bose-Hubbard models. Another central idea of this review concerns atomic simulators of paradigmatic models of particle physics theory such as the Creutz-Hubbard ladder, or Gross-Neveu-Wilson and Wilson-Hubbard models. This article is not a general review of the rapidly growing field-it reviews activities related to quantum simulations for lattice field theories performed by the Quantum Optics Theory group at ICFO and their collaborators from 19 institutions all over the world. Finally, we will briefly describe our efforts to design experimentally friendly simulators of these and other models relevant for particle physics. This article is part of the theme issue 'Quantum technologies in particle physics'.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close The central idea of this review is to consider quantum field theory models relevant for particle physics and replace the fermionic matter in these models by a bosonic one. This is mostly motivated by the fact that bosons are more áccessible' and easier to manipulate for experimentalists, but this 'substitution' also leads to new physics and novel phenomena. It allows us to gain new information about among other things confinement and the dynamics of the deconfinement transition. We will thus consider bosons in dynamical lattices corresponding to the bosonic Schwinger or [Formula: see text] Bose-Hubbard models. Another central idea of this review concerns atomic simulators of paradigmatic models of particle physics theory such as the Creutz-Hubbard ladder, or Gross-Neveu-Wilson and Wilson-Hubbard models. This article is not a general review of the rapidly growing field-it reviews activities related to quantum simulations for lattice field theories performed by the Quantum Optics Theory group at ICFO and their collaborators from 19 institutions all over the world. Finally, we will briefly describe our efforts to design experimentally friendly simulators of these and other models relevant for particle physics. This article is part of the theme issue 'Quantum technologies in particle physics'. Close https://royalsocietypublishing.org/doi/10.1098/rsta.2021.0064 doi:10.1098/rsta.2021.0064 Close