Article
Physics, Fluids & Plasmas
Matthew Gerry, Dvira Segal
Summary: Recently, a unified quantum master equation has been derived, which describes the dynamics of open quantum systems with coherences between nearly degenerate energy levels. The equation is shown to satisfy fluctuation symmetry and is thermodynamically consistent, making it more accurate than the fully secular master equation. Using this unified equation, the statistics of energy currents through open quantum systems have been investigated, and it has been found that maintaining coherences is essential in capturing the current and its cumulants.
Article
Physics, Multidisciplinary
Alexei D. Kiselev, Ranim Ali, Andrei Rybin
Summary: This paper investigates the thermal bath Lindblad master equation to describe the nonunitary dynamics of quantum states in a multi-mode bosonic system, and analyzes how the coupling between modes and with the environment affect entanglement dynamics. It discusses how entanglement revivals can be induced by dynamic coupling between different modes, and shows that reorientation of the relaxation rate vector can significantly increase the time of disentanglement in the regime of finite-time disentanglement.
Article
Physics, Multidisciplinary
Felix Pollock, Emanuel Gull, Kavan Modi, Guy Cohen
Summary: In this article, a theory of modified reduced dynamics in the presence of counting fields is presented. By considering counting fields, a variety of mixed system-environment observables and their statistical properties can be evaluated. The study demonstrates that the long-lived full counting statistics can be efficiently obtained from the reduced dynamics by numerically simulating the field-modified dynamics.
Article
Physics, Multidisciplinary
Chao Zhang, Fuming Xu, Jian Wang
Summary: The study examines the suitability of using the coherent potential approximation within full counting statistics formalism to investigate electric conductance, shot noise, and higher order cumulants in disordered systems. A similar FCS-CPA formalism was developed for phonon transport through disordered systems, revealing relationships among coefficients of different phonon current cumulants. Application of the FCS-CPA method in investigating phonon transport properties of graphene systems in the presence of disorders showed strong agreement with numerical results from the brute force method and achieved a 20 times speedup ratio, with collective features of phonon current cumulants also being revealed.
FRONTIERS OF PHYSICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Hisham Ba Omar, Miguel Angel Escobedo, Ajaharul Islam, Michael Strickland, Sabin Thapa, Peter Vander Griend, Johannes Heinrich Weber
Summary: We introduce an open-source package called QTraj that solves the Lindblad equation for heavy-quarkonium dynamics using the quantum trajectories algorithm.
COMPUTER PHYSICS COMMUNICATIONS
(2022)
Article
Quantum Science & Technology
Ralf Betzholz, Bruno G. Taketani, Juan Mauricio Torres
Summary: In this work, the differences between a common phenomenological model for the master equation and the more rigorous dressed-state master equation for optomechanical systems are investigated. An analytical method to obtain the absorption spectrum of the system for both models is provided, showing the breakdown of the phenomenological model in both the bad cavity and the ultra-strong coupling limit. The role of indirect dephasing of the optical cavity in both models and its impact on the predicted absorption spectra differences is discussed. This work offers a simple experimental test to determine whether the phenomenological model can accurately describe the system and is a step towards better understanding the role of coupling between subsystems for open-quantum-system dynamics.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Physics, Multidisciplinary
Yan He, Chih-Chun Chien
Summary: In this study, the Lindblad quantum master equation is applied to investigate the particle and thermal transport in one-dimensional topological systems, including the Su-Schrieffer-Heeger (SSH) model and Kitaev chain. The steady-state properties are obtained through the decomposition of fermions into Majorana fermions and the extraction of their correlation functions. The focus is on the particle and thermal currents flowing through the bulk when the system is driven by two reservoirs. The results reveal contrasting topological properties in quantum transport for the SSH model and the Kitaev chain.
Article
Physics, Multidisciplinary
Matteo Secli, Massimo Capone, Marco Schiro
Summary: We investigate the signatures of a self-trapping transition in a driven-dissipative Bose Hubbard dimer with incoherent pump and single-particle losses. The study focuses on the quantum dynamics of particle imbalance and frequency-resolved spectral properties of the steady state, showing clear evidence of a localization-delocalization crossover. A finite pump-loss asymmetry restores a delocalization crossover in the imbalance and leads to finite intra-dimer dissipation.
NEW JOURNAL OF PHYSICS
(2021)
Article
Mechanics
Thomas Barthel, Yikang Zhang
Summary: This article investigates the dynamics of Markovian open quantum systems, deriving the equation of motion for the covariance matrix in quasi-free systems. The use of ladder super-operators allows for the transformation of the Liouvillian to a many-body Jordan normal form, uncovering the full many-body spectrum. The article extends previous work, treating fermionic and bosonic systems equally and covering additional phenomena such as non-diagonalizable Liouvillians and quadratic systems.
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
(2022)
Article
Multidisciplinary Sciences
Nikolai M. Bogoliubov, Andrei V. Rybin
Summary: We study the quantum dynamics of the opened three-level su(1, 1) bosonic model and construct effective non-Hermitian Hamiltonians using the Lindblad equation. The obtained Hamiltonians are solvable using the Algebraic Bethe Ansatz, allowing us to represent biorthogonal and nonorthogonal bases of the system. By analyzing the biorthogonal expectation values of particles in the zero mode, we present it in a determinantal form. Additionally, we find the time-dependent density matrix satisfying the Lindblad master equation in terms of the nonorthogonal basis.
Article
Materials Science, Multidisciplinary
Balazs Dora, Catalin Pascu Moca
Summary: In this study, non-Hermitian many-body physics is investigated in the interacting Hatano-Nelson model with an open boundary condition. It is found that the violation of reciprocity caused by an imaginary vector potential leads to the non-Hermitian skin effect and exponential localization of all single-particle eigenfunctions in the noninteracting limit. However, in the interacting system, the density profile only slightly deviates from the average filling. The Friedel oscillations exhibit a beating pattern due to the modification of the Fermi wave number. It is confirmed by various numerical methods that the probability distribution of particles over any finite interval follows a normal distribution, with the mean scaling with the imaginary vector potential and the variance symmetric to the center of the chain. These findings are expected to apply not only to fermions but also to interacting bosons. The study highlights the significant impact of many-body effects on the properties and behavior of single-particle systems in non-Hermitian systems.
Article
Physics, Multidisciplinary
Vasily E. Tarasov
Summary: In this paper, an exactly solvable model of non-Markovian dynamics of open quantum systems is proposed, which describes open quantum systems with power-law fading memory. The non-Markovian quantum dynamics are described by using integrations and differentiations of non-integer orders, as well as fractional calculus.
Article
Optics
Julian K. Nauth
Summary: This paper presents a new approach to efficiently compute and predict the time-dependent counting statistics of highly entangled biphoton states. The approach is valid for a wide range of entanglement and arbitrary interaction times, taking into account general spatial modes for free space and fiber propagation. Different widths of time intervals provide access to accidental correlations between separated time intervals. The approach is also applicable to a modular array of arbitrary optical components and external influences.
Article
Physics, Multidisciplinary
Alberto Rolandi, Marti Perarnau-Llobet, Harry J. D. Miller
Summary: To achieve efficient and reliable control of microscopic systems, it is important to find driving protocols that minimize both average dissipation and stochastic fluctuations in work. In rapidly driven classical and quantum systems, we have characterized these optimal protocols, showing that they involve two discontinuous jumps in the full set of control variables. These jumps can be adjusted to interpolate between processes with minimal dissipation or minimal fluctuations, and sometimes allow for simultaneous minimization. We have demonstrated our general results using rapidly driven closed quantum systems, classical bit erasure, and a dissipative Ising chain driven close to a quantum phase transition.
NEW JOURNAL OF PHYSICS
(2023)
Article
Astronomy & Astrophysics
Yusuke Nishida
Summary: This study investigates the probability distribution of particle and antiparticle pairs produced via the Schwinger effect under the influence of a time-dependent electric field. The findings suggest that pair production is enhanced or suppressed in a medium for scalars or spinors respectively, due to Bose stimulation or Pauli blocking. Additionally, the annihilation of decelerated pairs is observed, along with the extraction of probability distributions in various scenarios using specialized statistics.
Article
Chemistry, Multidisciplinary
Remko Fermin, Dyon van Dinter, Michel Hubert, Bart Woltjes, Mikhail Silaev, Jan Aarts, Kaveh Lahabi
Summary: This study develops nanostructured Josephson junctions with highly controllable spin texture and induces long-range triplet (LRT) superconductivity in a ferromagnet through the interaction between the vortex magnetization of Co and the Cooper pairs of Nb. Surprisingly, the LRT correlations emerge only in highly localized channels at the rim of the ferromagnet, despite its trivial band structure.
Article
Physics, Multidisciplinary
Risto Ojajarvi, F. S. Bergeret, M. A. Silaev, Tero T. Heikkila
Summary: This paper investigates the influence of spin supercurrent phenomenon between superconductor and ferromagnet on magnetization dynamics. By observing magnetic hysteresis and ferromagnetic resonance response in experiments, the analog of the current-phase relation is determined and the mechanism of spin supercurrent is explored.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
E. Strambini, M. Spies, N. Ligato, S. Ilic, M. Rouco, Carmen Gonzalez-Orellana, Maxim Ilyn, Celia Rogero, F. S. Bergeret, J. S. Moodera, P. Virtanen, T. T. Heikkila, F. Giazotto
Summary: Diodes are important elements in electronics and optics, and their evolution towards low dissipation electronics has led to the development of supercurrent diodes with zero resistance in one direction. In this study, researchers demonstrate a superconducting tunnel diode with zero conductance in one direction by utilizing a thin ferromagnetic insulator. This cryogenic spintronic rectifier shows promise in highly-sensitive radiation detection and future low-dissipation and fast superconducting electronics.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Applied
Stefan Ilic, Pauli Virtanen, Tero T. Heikkila, F. Sebastian Bergeret
Summary: Spin-split superconductors exhibit an electron-hole asymmetric spin-resolved density of states, but the symmetry is restored upon averaging over spin. On the other hand, asymmetry appears again in tunneling junctions of spin-split superconductors with a spin-polarized barrier. This work demonstrates the important effect of electron-hole asymmetry on current rectification in spin-polarized tunnel junctions and discusses potential applications in superconducting electronics and radiation detectors.
PHYSICAL REVIEW APPLIED
(2022)
Review
Physics, Condensed Matter
I. Bobkova, A. M. Bobkov, M. A. Silaev
Summary: The review focuses on the fundamental aspects and characteristic features of magnetoelectric effects in Josephson junctions (JJs), discussing the direct and inverse magnetoelectric effects in various types of Josephson systems. It highlights the coupling of magnetization in JJs with the Josephson current and the importance of these effects for electrical control of magnetization. Additionally, the review explores the perspectives of coupling magnetization in JJs with ferromagnetic interlayers to the Josephson current through magnetoelectric effects.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Alberto Hijano, Sakineh Vosoughi-nia, F. Sebastian Bergeret, Pauli Virtanen, Tero T. Heikkila
Summary: We extended the Mattis-Bardeen theory to include various types of Hall responses in superconductors. By modifying the quasiclassical Usadel equation, we were able to analyze Hall effects in disordered superconductors and consider the precise frequency dependence of these effects. Our results provide a foundation for analyzing dynamic experiments, particularly in novel thin-film superconductors where ordinary Hall and spin Hall effects can occur simultaneously.
Article
Materials Science, Multidisciplinary
Benedikt Probst, Pauli Virtanen, Patrik Recher
Summary: In this paper, we investigate the isotropic exchange coupling of helical edge states to a spin 1/2 impurity in a two-dimensional topological insulator. We find that this coupling results in characteristic backscattering current noise, which exhibits transitions from sub-Poissonian to super-Poissonian behavior depending on the bias voltage and tilt angle. We use the method of full counting statistics and the master equation approach to analyze the behavior and provide a precise interpretation of the Fano factor in terms of electron bunching and antibunching.
Article
Materials Science, Multidisciplinary
Yao Lu, Risto Ojajarvi, P. Virtanen, M. A. Silaev, Tero T. Heikkila
Summary: We demonstrate that the Higgs mode and spin dynamics can couple together in superconductors with a static spin-splitting field and Rashba spin-orbit coupling. This coupling greatly modifies the spin susceptibility near the superconducting critical temperature and enhances the spin pumping effect in a ferromagnetic insulator/superconductor bilayer system. We also show that this effect can be detected by measuring the magnon transmission rate and the magnon-induced voltage through the inverse spin Hall effect.
Article
Materials Science, Multidisciplinary
Yao Lu, P. Virtanen, Tero T. Heikkila
Summary: We propose a method to directly probe the chirality of Majorana edge states in 2D topological superconductors using polarization selective photon absorption. The experimental results demonstrate that the chirality of the Majorana edge states can be obtained by measuring the photon absorption rate.
Article
Materials Science, Multidisciplinary
P. Virtanen, F. S. Bergeret, I. Tokatly
Summary: In this paper, we derive a nonlinear ℝ model to describe the diffusive transport in normal metals and superconductors with intrinsic spin-orbit coupling (SOC). The SOC is characterized by an SU(2) gauge field, and we expand the model to the fourth order in gradients to identify the leading non-Abelian field-strength contribution. This contribution gives rise to the spin-charge coupling responsible for the spin-Hall effect. We also obtain the corresponding Usadel equation to describe the diffusive spin-charge dynamics in superconducting systems and apply it to describe the anomalous supercurrent in dirty Rashba superconductors at arbitrary temperatures.
Article
Physics, Multidisciplinary
R. Haller, G. Fulop, D. Indolese, J. Ridderbos, R. Kraft, L. Y. Cheung, J. H. Ungerer, K. Watanabe, T. Taniguchi, D. Beckmann, R. Danneau, P. Virtanen, C. Schonenberger
Summary: Gate-tunable Josephson junctions embedded in a microwave environment are a promising platform for engineering and optimizing superconducting quantum circuits. In this study, the authors investigate a graphene-based Josephson junction enclosed in a SQUID loop, and extract important information about the phase-dependent junction admittance.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Faluke Aikebaier, Tero T. Heikkila, J. L. Lado
Summary: In this study, a ferromagnet/NbSe2/ferromagnet heterostructure is proposed, where the interplay between spin-orbit coupling and superconductivity controls the magnetic alignment of the heterostructure. The results also show that this coupling can induce a magnetic phase transition in the heterostructure when superconductivity is present.
