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An approach to the quantum-classical mechanics of phase space dependent operators, which has been proposed recently, is remodeled as a formalism for wave fields. Such wave fields obey a system of coupled non-linear equations that can be…

Quantum Physics · Physics 2007-05-23 Alessandro Sergi

We review recent developments in the theory of quantum dynamics in ultra-cold atomic physics, including exact techniques, but focusing on methods based on phase-space mappings that are appli- cable when the complexity becomes exponentially…

An Ising model with local Glauber dynamics is studied under the influence of additional kinetic restrictions for the spin-flip rates depending on the orientation of neighboring spins. Even when the static interaction between the spins is…

Statistical Mechanics · Physics 2009-10-31 Steffen Trimper

The need for strategies able to accurately manipulate quantum dynamics is ubiquitous in quantum control and quantum information processing. We investigate two scenarios where randomized dynamical decoupling techniques become more…

Quantum Physics · Physics 2009-11-13 Lorenza Viola , Lea F. Santos

Ensembles of alkali or noble-gas atoms at room temperature and above are widely applied in quantum optics and metrology owing to their long-lived spins. Their collective spin states maintain nonclassical nonlocal correlations, despite the…

Quantum Physics · Physics 2020-08-04 Roy Shaham , Or Katz , Ofer Firstenberg

Quantum simulation can help us study poorly understood topics such as high-temperature superconductivity and drug design. However, existing quantum simulation algorithms for current quantum computers often have drawbacks that impede their…

Quantum Physics · Physics 2022-02-28 Kishor Bharti , Tobias Haug

We develop a real-time Full Configuration Interaction Quantum Monte Carlo approach for the modeling of driven-dissipative open quantum systems. The method enables stochastic sampling of the Liouville-von-Neumann time evolution of the…

Quantum Physics · Physics 2018-06-06 Alexandra Nagy , Vincenzo Savona

We present a numerical scheme for simulating the 2D quantum dynamics of a two-level particle gas with internal degrees of freedom such as spin, pseudo-spin, or a two-band electronic structure. We adopt the Wigner formulation of quantum…

Mathematical Physics · Physics 2026-04-10 O. Morandi

Variational Quantum Algorithms are among the most promising systems to implement quantum computing under the Noisy-Intermediate Scale Quantum (NISQ) technology. In variational quantum algorithm, wavefunction represented by a parametrized…

Quantum Physics · Physics 2023-01-02 H. Davoodi Yeganeh

A variational principle is further developed for out of equilibrium dynamical systems by using the concept of maximum entropy. With this new formulation it is obtained a set of two first-order differential equations, revealing the same…

Data Analysis, Statistics and Probability · Physics 2019-03-22 Mario J. Pinheiro

We study Bosonic representation of spin Ising model with the application of simulating two level systems using continuous variable quantum processors. We decompose the time evolution of spin systems into a sequence of continuous variable…

Quantum Physics · Physics 2020-09-29 Razieh Annabestani , Brajesh Gupt , Bhaskar Roy Bardhan

The physics of a closed quantum mechanical system is governed by its Hamiltonian. However, in most practical situations, this Hamiltonian is not precisely known, and ultimately all there is are data obtained from measurements on the system.…

This thesis deals with the study of dynamical properties of out-of-equilibrium quantum systems. We introduce in particular a general class of Spin-Boson models, which describe for example light-matter interaction or dissipative phenomena.…

Mesoscale and Nanoscale Physics · Physics 2018-04-17 Loïc Henriet

We address the quantum dynamics of a system composed of a qubit globally coupled to a many-body system characterized by short-range interactions. We employ a dynamic finite-size scaling framework to investigate the out-of-equilibrium…

Statistical Mechanics · Physics 2019-05-20 Davide Rossini , Ettore Vicari

Geometric frustration in two-dimensional Ising models allows for a wealth of exotic universal behavior, both Ising and non-Ising, in the presence of quantum fluctuations. In particular, the triangular antiferromagnet and Villain model in a…

Quantum Physics · Physics 2025-02-13 Ammar Ali , Hanjing Xu , William Bernoudy , Alberto Nocera , Andrew D. King , Arnab Banerjee

We develop dynamical programming methods for the purpose of optimal control of quantum states with convex constraints and concave cost and bequest functions of the quantum state. We consider both open loop and feedback control schemes,…

Quantum Physics · Physics 2009-03-06 Viacheslav P. Belavkin , Antonio Negretti , Klaus Molmer

We investigate non-equilibrium quantum spin systems via an exact mapping to stochastic differential equations. This description is invariant under a shift in the mean of the Gaussian noise. We show that one can extend the simulation time…

Strongly Correlated Electrons · Physics 2021-12-28 S. E. Begg , A. G. Green , M. J. Bhaseen

A dynamical quantum phase transition can occur during time evolution of sudden quenched quantum systems across a phase transition. It corresponds to the nonanalytic behavior at a critical time of the rate function of the quantum state…

Quantum Physics · Physics 2019-05-14 Xue-Yi Guo , Chao Yang , Yu Zeng , Yi Peng , He-Kang Li , Hui Deng , Yi-Rong Jin , Shu Chen , Dongning Zheng , Heng Fan

We introduce an optimisation method for variational quantum algorithms and experimentally demonstrate a 100-fold improvement in efficiency compared to naive implementations. The effectiveness of our approach is shown by obtaining…

The quantum Kibble-Zurek mechanism (QKZM) predicts universal dynamical behavior near the quantum phase transitions (QPTs). It is now well understood for the one-dimensional quantum matter. Higher-dimensional systems, however, remain a…

Strongly Correlated Electrons · Physics 2022-10-26 Markus Schmitt , Marek M. Rams , Jacek Dziarmaga , Markus Heyl , Wojciech H. Zurek