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Variational quantum algorithms are one of the most promising methods that can be implemented on noisy intermediate-scale quantum (NISQ) machines to achieve a quantum advantage over classical computers. This article describes the use of a…

Quantum Physics · Physics 2022-05-10 Wei-Bin Ewe , Dax Enshan Koh , Siong Thye Goh , Hong-Son Chu , Ching Eng Png

Quantum and classical systems evolving under the same formal Hamiltonian $H$ may dramatically differ after the Ehrenfest timescale $t_E \sim \log(\hbar^{-1})$, even as $\hbar \to 0$. Coupling the system to a Markovian environment results in…

Mathematical Physics · Physics 2025-05-20 Felipe Hernández , Daniel Ranard , C. Jess Riedel

Quantum steering describes how local actions on a quantum system can affect another, space-like separated, quantum state. Lately, quantum steering has been formulated also for time-like scenarios and for quantum channels. We approach all…

Quantum Physics · Physics 2018-03-07 Roope Uola , Fabiano Lever , Otfried Gühne , Juha-Pekka Pellonpää

An expression of the Lindbladian form is proposed that ensures an unambiguous time-continuous reduction of the initial system-pointer wave-packet to one in which the readings and the observable's values are aligned, formalized as the…

Quantum Physics · Physics 2023-01-10 Robert Englman , Asher Yahalom

We present a general formalism based on the variational principle for finding the time-optimal quantum evolution of mixed states governed by a master equation, when the Hamiltonian and the Lindblad operators are subject to certain…

Quantum Physics · Physics 2014-12-01 A. Carlini , A. Hosoya , T. Koike , Y. Okudaira

In open quantum systems, a basic question at the interface of quantum information, statistical physics, and many-body dynamics is how well can one infer the structure of noise and dissipation generators from finite-time measurement…

Quantum Physics · Physics 2026-01-06 Caisheng Cheng , Ruicheng Bao

Recently, a generalization of the standard optical multiport was proposed [Phys. Rev. A 93, 043845 (2016)]. These directionally unbiased multiports allow photons to reverse direction and exit backwards from the input port, providing a…

Quantum Physics · Physics 2017-04-12 David S. Simon , Casey A. Fitzpatrick , Shuto Osawa , Alexander V. Sergienko

Quantum control protocols are typically devised in the time domain, leaving their spectral behavior to emerge only a posteriori. Here, we invert this paradigm. Starting from a target frequency-domain filter, we employ the…

Quantum Physics · Physics 2025-06-23 Loris Maria Cangemi , Yoav Woldiger , Amikam Levy , Assaf Hamo

Quantum simulation is one of the most promising scientific applications of quantum computers. Due to decoherence and noise in current devices, it is however challenging to perform digital quantum simulation in a regime that is intractable…

The Lindblad equation generalizes the Schr\"{o}dinger equation to quantum systems that undergo dissipative dynamics. The quantum simulation of Lindbladian dynamics is therefore non-unitary, preventing a naive application of state-of-the-art…

Quantum Physics · Physics 2025-03-20 Matthew Pocrnic , Dvira Segal , Nathan Wiebe

We consider the extent to which a Trotterized time evolution implemented on a quantum computer is altered by the presence of decoherence. Given a specific set of assumptions regarding the manner in which noise processes acting on such a…

The representation of a quantum wave function as a neural network quantum state (NQS) provides a powerful variational ansatz for finding the ground states of many-body quantum systems. Nevertheless, due to the complex variational landscape,…

Quantum Physics · Physics 2023-12-06 Eimantas Ledinauskas , Egidijus Anisimovas

We study a qDRIFT-type randomized method to simulate Lindblad dynamics by decomposing its generator into an ensemble of Lindbladians, $\mathcal{L} = \sum_{a \in \mathcal{A}} \mathcal{L}_a$, where each $\mathcal{L}_a$ comprises a simple…

Quantum Physics · Physics 2025-11-26 Hongrui Chen , Bowen Li , Jianfeng Lu , Lexing Ying

We propose a new variational quantum algorithm, which we refer to as TIMES-ADAPT, that prepares time-evolved states in a low-energy or symmetric subspace of a time-independent Hamiltonian on a quantum computer. Using a specially trained…

The Lindblad master equation is one of the main approaches to open quantum systems. While it has been widely applied in the context of condensed matter systems to study properties of steady states in the limit of long times, the actual…

Statistical Mechanics · Physics 2023-08-07 Tjark Heitmann , Jonas Richter , Jacek Herbrych , Jochen Gemmer , Robin Steinigeweg

The dynamics of open quantum systems is formulated in a minimally extended state space comprising the degrees of freedom of a system of interest and a finite set of non-unitary, pure-state reservoir modes. This formal structure, derived…

Quantum Physics · Physics 2023-08-01 Meng Xu , Vasilii Vadimov , Malte Krug , J. T. Stockburger , J. Ankerhold

Entanglement-breaking channels are quantum channels transforming entangled states to separable states. Despite a detailed discussion of their operational structure, to be found in the literature, studies on dynamical characteristics of this…

Quantum Physics · Physics 2023-03-08 Fattah Sakuldee , Łukasz Rudnicki

Dissipation can be used as a resource to control and simulate quantum systems. We discuss a modular model based on fast dissipation capable of performing universal quantum computation, and simulating arbitrary Lindbladian dynamics. The…

Quantum Physics · Physics 2016-12-01 Jeffrey Marshall , Lorenzo Campos Venuti , Paolo Zanardi

In this work, we develop a protocol for learning a time-independent Lindblad model for operations that can be applied repeatedly on a quantum computer. The protocol is highly scalable for models with local interactions and is in principle…

Quantum Physics · Physics 2025-12-10 Ewout van den Berg , Brad Mitchell , Ken Xuan Wei , Moein Malekakhlagh

Accurate characterization of quantum systems is essential for the development of quantum technologies, particularly in the noisy intermediate-scale quantum (NISQ) era. While traditional methods for Hamiltonian learning and noise…

Quantum Physics · Physics 2025-07-18 Gubio G. de Lima , Iann Cunha , Leonardo Kleber Castelano