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Quantum variational algorithms have garnered significant interest recently, due to their feasibility of being implemented and tested on noisy intermediate scale quantum (NISQ) devices. We examine the robustness of the quantum approximate…

Quantum Physics · Physics 2019-11-05 Yulong Dong , Xiang Meng , Lin Lin , Robert Kosut , K. Birgitta Whaley

The energy variance optimization algorithm over a fixed ensemble of configurations in variational Monte Carlo is formally identical to a problem of fitting data: we reexamine it from a statistical maximum-likelihood point of view. We detect…

Atomic and Molecular Clusters · Physics 2009-11-07 Dario Bressanini , Gabriele Morosi , Massimo Mella

This study investigates the thermal properties of the repulsive Fermi-Hubbard model with chemical potential using variational quantum algorithms, crucial in comprehending particle behaviour within lattices at high temperatures in condensed…

Quantum Physics · Physics 2024-06-17 Jack Y. Araz , Michael Spannowsky , Matthew Wingate

We introduce a variational hybrid classical-quantum algorithm to simulate the Lindblad master equation and its adjoint for time-evolving Markovian open quantum systems and quantum observables. Our method is based on a direct representation…

Quantum Physics · Physics 2023-05-19 Tasneem Watad , Netanel H. Lindner

Recently a method for adiabatic quantum computation has been proposed and there has been considerable speculation about its efficiency for NP-complete problems. Heuristic arguments in its favor are based on the unproven assumption of an…

Quantum Physics · Physics 2007-05-23 Mary Beth Ruskai

Variational quantum algorithms have been one of the most intensively studied applications for near-term quantum computing applications. The noisy intermediate-scale quantum (NISQ) regime, where small enough algorithms can be run…

Quantum Physics · Physics 2023-01-19 Sebastian Brandhofer , Simon Devitt , Ilia Polian

We consider a quantum-mechanical analysis of spontaneous emission in terms of an effective two-level system with a vacuum decay rate $\Gamma_0$ and transition angular frequency $\omega_A$. Our analysis is in principle exact, even though…

Quantum Physics · Physics 2013-05-30 Arne L. Grimsmo , Asle H. Vaskinn , Per K. Rekdal , Bo-Sture K. Skagerstam

In this study, we propose a new method for constrained combinatorial optimization using variational quantum circuits. Quantum computers are considered to have the potential to solve large combinatorial optimization problems faster than…

Quantum Physics · Physics 2025-07-15 Hyakka Nakada , Kotaro Tanahashi , Shu Tanaka

Exact and nonperturbative quantum master equation can be constructed via the calculus on path integral. It results in hierarchical equations of motion for the reduced density operator. Involved are also a set of well--defined auxiliary…

Statistical Mechanics · Physics 2015-05-13 Jian Xu , Rui-Xue Xu , YiJing Yan

We investigate the computational power of creating steady-states of quantum dissipative systems whose evolution is governed by time-independent and local couplings to a memoryless environment. We show that such a model allows for efficient…

Quantum Physics · Physics 2009-09-24 Frank Verstraete , Michael M. Wolf , J. Ignacio Cirac

Classical algorithms for predicting the equilibrium geometry of strongly correlated molecules require expensive wave function methods that become impractical already for few-atom systems. In this work, we introduce a variational quantum…

A key issue in dimension reduction of dissipative dynamical systems with spectral gaps is the identification of slow invariant manifolds. We present theoretical and numerical results for a variational approach to the problem of computing…

Dynamical Systems · Mathematics 2012-11-30 Dirk Lebiedz , Jochen Siehr , Jonas Unger

We propose a new method to obtain kinetic properties of infrequent events from molecular dynamics simulation. The procedure employs a recently introduced variational approach [Valsson and Parrinello, Phys. Rev. Lett. 113, 090601 (2014)] to…

Statistical Mechanics · Physics 2015-08-19 James McCarty , Omar Valsson , Pratyush Tiwary , Michele Parrinello

Imaginary time evolution is a powerful tool for studying quantum systems. While it is possible to simulate with a classical computer, the time and memory requirements generally scale exponentially with the system size. Conversely, quantum…

Quantum Physics · Physics 2019-09-17 Sam McArdle , Tyson Jones , Suguru Endo , Ying Li , Simon Benjamin , Xiao Yuan

Variational optimization of orbitals in time-independent density functional calculations of excited electronic states presents a significant challenge, as excited states typically correspond to saddle points on the electronic energy…

Chemical Physics · Physics 2026-04-02 Yorick L. A. Schmerwitz , Elli Selenius , Gianluca Levi

In this work, we discuss two modifications that can be made to a known variational quantum singular value decomposition algorithm popular in the literature. The first is a change to the objective function which hints at improved performance…

Quantum Physics · Physics 2024-12-05 Jezer Jojo , Ankit Khandelwal , M Girish Chandra

This Ph.D. thesis provides a comprehensive review of the state-of-the-art in the field of Variational Quantum Algorithms and Quantum Machine Learning, including numerous original contributions. The first chapters are devoted to a brief…

Quantum Physics · Physics 2023-06-19 Stefano Mangini

We investigate the steering dissipative dynamics of a two-level system (qubit) by means of the modulation of an assisted tunneling degree of freedom which is described by a quantum-oscillator spin-boson model. Our results reveal that the…

Quantum Physics · Physics 2022-04-07 Zhiguo Lü , Hang Zheng

We propose a distributionally robust model for the influence maximization problem. Unlike the classic independent cascade model \citep{kempe2003maximizing}, this model's diffusion process is adversarially adapted to the choice of seed set.…

Social and Information Networks · Computer Science 2022-02-23 Louis Chen , Divya Padmanabhan , Chee Chin Lim , Karthik Natarajan

The power method (or iteration) is a well-known classical technique that can be used to find the dominant eigenpair of a matrix. Here, we present a variational quantum circuit method for the power iteration, which can be used to find the…

Quantum Physics · Physics 2021-10-08 Ammar Daskin