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We use Wegner's flow equation method to investigate the infinite-$U$ periodic Anderson model. We show that this method poses a new approach to the description of heavy fermion behaviour. Within this scheme we derive an effective Hamiltonian…

Strongly Correlated Electrons · Physics 2009-11-10 Karsten Meyer

We build an exact framework to evaluate heat, energy, and particle transport between Gaussian reservoirs mediated by a quadratic quantum system. By combining full counting statistics with newly developed non-Markovian master equation…

Quantum Physics · Physics 2026-02-25 Guglielmo Pellitteri , Vittorio Giovannetti , Vasco Cavina

A two-dimensional lattice hard-core boson system with a small fraction of bosonic or fermionic impurity particles is studied. The impurities have the same hopping and interactions as the dominant bosons and their effects are solely due to…

Other Condensed Matter · Physics 2009-11-13 Anders. W. Sandvik

Quantum reservoir engineering leverages dissipative processes to achieve desired behavior, with applications ranging from entanglement generation to quantum error correction. Therein, a structured environment acts as an entropy sink for the…

Quantum Physics · Physics 2025-12-05 Marcelo Janovitch , Matteo Brunelli , Patrick P. Potts

We provide a detailed formulation of the recently proposed variational approach [Y. Ashida et al., Phys. Rev. Lett. 121, 026805 (2018)] to study ground-state properties and out-of-equilibrium dynamics for generic quantum spin-impurity…

Strongly Correlated Electrons · Physics 2018-07-13 Yuto Ashida , Tao Shi , Mari Carmen Bañuls , J. Ignacio Cirac , Eugene Demler

We theoretically investigate the pure dephasing dynamics of two static impurity qubits embedded within a common environment of ultracold fermionic atoms, which are confined to one spatial dimension. Our goal is to understand how…

Quantum Gases · Physics 2024-02-13 Sindre Brattegard , Mark T. Mitchison

Due to the exponential growth of the state space of coupled quantum systems it is not possible, in general, to numerically store the state of a very large number of quantum systems within a classical computer. We demonstrate a method for…

Quantum Physics · Physics 2017-02-07 J. J. Bowen , V. M. Dwyer , I. W. Phillips , M. J. Everitt

Quantum coherence inherently affects the dynamics and the performances of a quantum machine. Coherent control can, at least in principle, enhance the work extraction and boost the velocity of evolution in an open quantum system. Using…

Quantum Physics · Physics 2018-12-10 Vasco Cavina , Andrea Mari , Alberto Carlini , Vittorio Giovannetti

We investigate the out-of-equilibrium properties of a simple quantum impurity model, the interacting resonant level model (IRLM). We focus on the scaling regime, where the bandwidth of the fermions in the leads is larger than all the other…

Strongly Correlated Electrons · Physics 2017-12-06 Kemal Bidzhiev , Grégoire Misguich

We review recent work on continuous quantum phase transitions in impurity models, both with fermionic and bosonic baths - these transitions are interesting realizations of boundary critical phenomena at zero temperature. The models with…

Statistical Mechanics · Physics 2015-06-24 Matthias Vojta

We present a diagrammatic Monte Carlo method for quantum impurity problems with general interactions and general hybridization functions. Our method uses a recursive determinant scheme to sample diagrams for the scattering amplitude. Unlike…

Strongly Correlated Electrons · Physics 2020-08-13 Jia Li , Markus Wallerberger , Emanuel Gull

We generalize the recently developed diagrammatic Monte Carlo techniques for quantum impurity models from an imaginary time to a Keldysh formalism suitable for real-time and nonequilibrium calculations. Both weak-coupling and…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Philipp Werner , Takashi Oka , Andrew J. Millis

We theoretically investigate the non-equilibrium quantum dynamical theory of a quantum dot system coupled to fermionic reservoirs using the recently developed stochastic fermionic quantum state diffusion (FQSD) equation. The exact or…

Quantum Physics · Physics 2018-12-07 Wufu Shi , Yusui Chen , Lihui Sun , J. Q. You , Ting Yu

We investigate the ground-state properties of the Anderson single impurity model (finite Coulomb impurity repulsion) with the Coupled Cluster Method. We consider different CCM reference states and approximation schemes and make comparison…

Strongly Correlated Electrons · Physics 2009-06-26 Jin-Jun Liang , Clive Emary , Tobias Brandes

We propose a non-linear, hybrid quantum-classical scheme for simulating non-equilibrium dynamics of strongly correlated fermions described by the Hubbard model in a Bethe lattice in the thermodynamic limit. Our scheme implements…

Quantum Physics · Physics 2016-09-14 J. M. Kreula , S. R. Clark , D. Jaksch

Impurities in quantum materials have provided successful strategies for learning properties of complex states, ranging from unconventional superconductors to topological insulators. In quantum magnetism, inferring the Hamiltonian of an…

Mesoscale and Nanoscale Physics · Physics 2025-06-23 Greta Lupi , Jose L. Lado

The numerical renormalization group method is used to investigate zero temperature phase transitions in quantum impurity systems, in particular in the soft-gap Anderson model, where an impurity couples to a non-trivial fermionic bath. In…

Strongly Correlated Electrons · Physics 2009-11-10 H. -J. Lee , R. Bulla

Noise is often regarded as a limitation of quantum computers. In this work, we show that in the dynamical mean field theory (DMFT) approach to strongly-correlated systems, it can actually be harnessed to our advantage. Indeed, DMFT maps a…

Quantum Physics · Physics 2025-08-01 Corentin Bertrand , Pauline Besserve , Michel Ferrero , Thomas Ayral

Simulating noninteracting fermion systems is a common task in computational many-body physics. In absence of translational symmetries, modeling free fermions on $N$ modes usually requires poly$(N)$ computational resources. While often…

Quantum Physics · Physics 2026-02-24 Maarten Stroeks , Daan Lenterman , Barbara Terhal , Yaroslav Herasymenko

While general quantum many-body systems require exponential resources to be simulated on a classical computer, systems of non-interacting fermions can be simulated exactly using polynomially scaling resources. Such systems may be of…

Strongly Correlated Electrons · Physics 2019-12-18 Norbert Schuch , Bela Bauer