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We present a general variational principle for the dynamics of impurity particles immersed in a quantum-mechanical medium. By working within the Heisenberg picture and constructing approximate time-dependent impurity operators, we can take…

Quantum Gases · Physics 2019-05-29 Weizhe Edward Liu , Jesper Levinsen , Meera M. Parish

We consider periodically driven potential impurities coupled to the surface states of a two-dimensional topological insulator. The problem is addressed by means of two models, out which the first model is an effective continuum Hamiltonian…

Strongly Correlated Electrons · Physics 2019-10-02 Saurabh Pradhan , Jonas Fransson

Using an imaginary-time matrix-product state (MPS) based quantum impurity solver we perform a realistic dynamical mean-field theory (DMFT) calculation combined with density functional theory (DFT) for Sr$_2$RuO$_4$. We take the full…

Strongly Correlated Electrons · Physics 2020-01-22 Nils-Oliver Linden , Manuel Zingl , Claudius Hubig , Olivier Parcollet , Ulrich Schollwöck

We consider the problem of a charged impurity exerting a weak, slowly decaying force on its surroundings, treating the latter as an ideal compressible fluid. In the semiclassical approximation, the ion is described by the Newton equation…

Quantum Gases · Physics 2025-04-17 Krzysztof Myśliwy , Piotr Wysocki , Krzysztof Jachymski

We provide an exact description of out-of-equilibrium fixed points in quantum impurity systems, that is able to treat time-dependent forcing. Building on this, we then show that analytical out-of-equilibrium results, that exactly treat…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 Loïc Freton , Edouard Boulat

We investigate quantum impurity problems, where a local magnetic moment is coupled to the spin density of a bosonic environment, leading to bosonic versions of the standard Kondo and Anderson impurity models. In a physical situation, these…

Strongly Correlated Electrons · Physics 2008-11-26 Serge Florens , Lars Fritz , Matthias Vojta

Developing numerical exact solvers for open quantum systems is a challenging task due to the non-perturbative and non-Markovian nature when coupling to structured environments. The Feynman-Vernon influence functional approach is a powerful…

Strongly Correlated Electrons · Physics 2024-10-16 Xiansong Xu , Chu Guo , Ruofan Chen

Describing non-equilibrium properties of quantum many-body systems is challenging due to high entanglement in the wavefunction. We describe evolution of local observables via the influence matrix (IM), which encodes the effects of a…

Quantum Physics · Physics 2023-03-01 Alessio Lerose , Michael Sonner , Dmitry A. Abanin

We review a systematic many-body method capable of describing Fermi liquid and Non-Fermi liquid behavior of quantum impurity models at low temperatures on the same footing. The crossover to the high temperature local moment regime is…

Strongly Correlated Electrons · Physics 2007-05-23 J. Kroha , P. Wölfle

The Grassmann time-evolving matrix product operator (GTEMPO) method, which represents the Feynman-Vernon influence functional as a temporal matrix product state, has been shown to be a flexible and potentially scalable solution for…

Strongly Correlated Electrons · Physics 2026-04-28 Chu Guo , Wei Wu , Xiansong Xu , Ping-Xing Chen , Changming Yue , Tian Jiang , Ruofan Chen

We apply the diagrammatic Monte Carlo approach to three-dimensional Fermi-polaron systems with mass-imbalance, where an impurity interacts resonantly with a noninteracting Fermi sea whose atoms have a different mass. This method allows to…

Quantum Gases · Physics 2015-04-23 Peter Kroiss , Lode Pollet

Nonequilibrium steady-state currents, unlike their equilibrium counterparts, continuously dissipate energy into their physical surroundings leading to entropy production and time-reversal symmetry breaking. This letter discusses these…

Strongly Correlated Electrons · Physics 2009-11-13 Pankaj Mehta , Natan Andrei

The notion of quasi-particles is essential for understanding the behaviour of complex many-body systems. A prototypical example of a quasi-particle, a polaron, is an impurity strongly interacting with a surrounding medium. Fermi polarons,…

We study in three dimensions the problem of a spatially homogeneous zero-temperature ideal Fermi gas of spin-polarized particles of mass $m$ perturbed by the presence of a single distinguishable impurity of mass $M$. The interaction between…

Quantum Gases · Physics 2015-06-19 Christian Trefzger , Yvan Castin

We study a quantum impurity coupled to the edge states of a two-dimensional helical topological superconductor, i.e., to a pair of counterpropagating Majorana fermion edge channels with opposite spin polarizations. For an impurity described…

Strongly Correlated Electrons · Physics 2011-11-15 Rok Zitko , Pascal Simon

The coupling between localized magnetic moments and itinerant electrons presents a plethora of interesting physics. The low-energy physics of some quantum impurity systems can be described using conformal field theory (CFT). In this paper,…

High Energy Physics - Theory · Physics 2019-11-26 Ying-Hai Wu , Hong-Hao Tu

In this paper, a novel feedback control-based particle filter algorithm for the continuous-time stochastic hybrid system estimation problem is presented. This particle filter is referred to as the interacting multiple model-feedback…

Numerical Analysis · Mathematics 2013-05-28 Tao Yang , Henk A. P. Blom , Prashant G. Mehta

The path integral formalism is the building block of many powerful numerical methods for quantum impurity problems. However, existing fermionic path integral based numerical calculations have only been performed in either the imaginary-time…

Strongly Correlated Electrons · Physics 2024-10-10 Ruofan Chen , Chu Guo

The fastest possible collective response of a quantum many-body system is related to its excitations at the highest possible energy. In condensed-matter systems, the corresponding timescale is typically set by the Fermi energy. Taking…

Temporal entanglement (TE) of an influence matrix (IM) has been proposed as a measure of complexity of simulating dynamics of local observables in a many-body system. Foligno et al. [Phys. Rev. X 13, 041008 (2023)] recently argued that the…