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A novel scheme to simulate the evolution of a restricted set of observables of a quantum system is proposed. The set comprises the spectrum-generating algebra of the Hamiltonian. The idea is to consider a certain open-system evolution,…

Quantum Physics · Physics 2009-11-13 M. Khasin , R. Kosloff

Estimating the dimension of an Hilbert space is an important component of quantum system identification. In quantum technologies, the dimension of a quantum system (or its corresponding accessible Hilbert space) is an important resource, as…

Quantum Physics · Physics 2018-01-04 Akira Sone , Paola Cappellaro

Quantum effects such as the environment assisted quantum transport (ENAQT) displayed in photosynthetic Fenna-Mathews-Olson (FMO) complex has been simulated on analog quantum simulators. Digital quantum simulations offer greater universality…

Quantum Physics · Physics 2020-12-11 Pragati Gupta , C. M. Chandrashekar

We study solutions to the quantum trajectory evolution of $N$-mode open quantum systems possessing a time-independent Hamiltonian, linear Heisenberg-picture dynamics, and Gaussian measurement noise. In terms of the mode annihilation and…

Quantum Physics · Physics 2020-10-21 P. Warszawski , H. M. Wiseman , A. C. Doherty

We introduce a relaxed-projection splitting algorithm for solving variational inequalities in Hilbert spaces for the sum of nonsmooth maximal monotone operators, where the feasible set is defined by a nonlinear and nonsmooth continuous…

Optimization and Control · Mathematics 2015-12-31 J. Y. Bello Cruz , R. Diaz Millan

We present and analyze the fermionic time evolving density matrix using orthogonal polynomials algorithm (fTEDOPA), which enables the numerically exact simulation of open quantum systems coupled to a fermionic environment. The method allows…

Quantum Physics · Physics 2020-05-08 Alexander Nüßeler , Ish Dhand , Susana F. Huelga , Martin B. Plenio

There is a growing attention given to utilizing Lagrangian and Hamiltonian mechanics with network training in order to incorporate physics into the network. Most commonly, conservative systems are modeled, in which there are no frictional…

Machine Learning · Computer Science 2024-05-28 Veera Sundararaghavan , Megna N. Shah , Jeff P. Simmons

A temporally varying discretization often features in discrete gravitational systems and appears in lattice field theory models subject to a coarse graining or refining dynamics. To better understand such discretization changing dynamics in…

General Relativity and Quantum Cosmology · Physics 2014-10-03 Philipp A. Hoehn

We propose a way to understand the evolution of an open quantum system using a description that dispenses a continuous evolution in time, by discrete operators entangled states, in its most direct and fundamental way. We show that the…

Quantum Physics · Physics 2016-02-17 Bernabé Mejía , Hernán A. Castillo

Efficient descriptions of open quantum systems can be obtained by performing an adiabatic elimination of the fast degrees of freedom and formulating effective operators for the slow degrees of freedom in reduced dimensions. Here, we perform…

Master equations in the Lindblad form describe evolution of open quantum systems that is completely positive and simultaneously has a semigroup property. We analyze a possibility to derive this type of master equations from an intrinsically…

Quantum Physics · Physics 2007-05-23 Mario Ziman , Peter Stelmachovic , Vladimir Buzek

The shell model solve the nuclear many-body problem in a restricted model space and takes into account the restricted nature of the space by using effective interactions and operators. In this paper two different methods for generating the…

Nuclear Theory · Physics 2009-11-11 B. K. Jennings

We derive a path-integral Schwinger-Keldysh approach for quantum spin systems. This is achieved by means of a semionic representation of spins as fermions with imaginary chemical potential. The major simplifying feature in comparison with…

Strongly Correlated Electrons · Physics 2009-10-31 M. N. Kiselev , R. Oppermann

We introduce the concept of fidelity for dynamical maps in an open quantum system scenario. We derive an inequality linking this quantity to the distinguishability of the inducing environmental states. Our inequality imposes constraints on…

Quantum Physics · Physics 2017-05-10 Mikko Tukiainen , Henri Lyyra , Gniewomir Sarbicki , Sabrina Maniscalco

The master equation for a linear open quantum system in a general environment is derived using a stochastic approach. This is an alternative derivation to that of Hu, Paz and Zhang, which was based on the direct computation of path…

General Relativity and Quantum Cosmology · Physics 2011-08-04 Esteban Calzetta , Albert Roura , Enric Verdaguer

We demonstrate the power of a first principle-based and practicable method that allows for the perturbative computation of reduced density matrix elements of an open quantum system without making use of any master equations. The approach is…

High Energy Physics - Theory · Physics 2023-06-12 Christian Käding , Mario Pitschmann

It is not possible, using standard lattice techniques in Euclidean space, to calculate the complete fermionic spectrum of a quantum field theory. Algorithms running on quantum computers have the potential to access the theory with real-time…

High Energy Physics - Lattice · Physics 2021-09-27 Giovanni Pederiva , Alexei Bazavov , Brandon Henke , Leon Hostetler , Dean Lee , Huey-Wen Lin , Andrea Shindler

In this paper, we investigate the spectral projection of density matrices in quantum field theory. With appropriate regularization, the spectral projectors of density matrices are expected to be well-defined. These projectors can be…

High Energy Physics - Theory · Physics 2025-08-29 Wu-zhong Guo

Instead of formulating the state space of a quantum field theory over one big Hilbert space, it has been proposed by Kijowski to describe quantum states as projective families of density matrices over a collection of smaller, simpler…

General Relativity and Quantum Cosmology · Physics 2016-12-28 Suzanne Lanéry , Thomas Thiemann

The central challenge for describing the dynamics in open quantum systems is that the Hilbert space of typical environments is too large to be treated exactly. In some cases, such as when the environment has a short memory time or only…