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We propose an experimentally accessible procedure for conditional preparation of highly non-classical states of collective spin of an atomic ensemble. The quantum state engineering is based on a combination of QND interaction between atoms…

Quantum Physics · Physics 2013-05-29 Karel Lemr , Jaromir Fiurasek

We propose an efficient scheme for generating spin-squeezed states at steady state in a spin-mechanical hybrid system, where an ensemble of SiV centers are coupled to a strongly damped nanomechanical resonator. We show that,there exists a…

Quantum Physics · Physics 2021-10-07 Jia-Qiang Chen , Yi-Fan Qiao , Xing-Liang Dong , Xin-Lei Hei , Peng-Bo Li

A protocol is discussed for preparing a spin chain in a generic many-body state in the asymptotic limit of tailored non-unitary dynamics. The dynamics require the spectral resolution of the target state, optimized coherent pulses,…

The preparation of thermal equilibrium states is important for the simulation of condensed-matter and cosmology systems using a quantum computer. We present a method to prepare such mixed states with unitary operators, and demonstrate this…

This paper explores the utility of the quantum phase estimation (QPE) in calculating high-energy excited states characterized by promotions of electrons occupying inner energy shells. These states have been intensively studied over the last…

The computation of excited states in strongly interacting quantum many-body systems is of fundamental importance. Yet, it is notoriously challenging due to the exponential scaling of the Hilbert space dimension with the system size. Here,…

Quantum Physics · Physics 2025-06-11 Yixuan Ma , Chang Liu , Weikang Li , Shun-Yao Zhang , L. -M. Duan , Yukai Wu , Dong-Ling Deng

Dynamical response functions are fundamental quantities to describe the excited-state properties in quantum many-body systems. Quantum algorithms have been proposed to evaluate these quantities by means of quantum phase estimation (QPE),…

Quantum Physics · Physics 2024-08-27 Rei Sakuma , Shu Kanno , Kenji Sugisaki , Takashi Abe , Naoki Yamamoto

A fundamental step of any quantum algorithm is the preparation of qubit registers in a suitable initial state. Often qubit registers represent a discretization of continuous variables and the initial state is defined by a multivariate…

We show that optimal control of the electron dynamics is able to prepare molecular ground states, within chemical accuracy, with evolution times approaching the bounds imposed by quantum mechanics. We propose a specific parameterization of…

Quantum Physics · Physics 2024-02-20 Davide Castaldo , Marta Rosa , Stefano Corni

We present a variational Monte Carlo algorithm for estimating the lowest excited states of a quantum system which is a natural generalization of the estimation of ground states. The method has no free parameters and requires no explicit…

Computational Physics · Physics 2024-09-04 David Pfau , Simon Axelrod , Halvard Sutterud , Ingrid von Glehn , James S. Spencer

Entanglement underpins the power of quantum technologies, yet it is fragile and typically destroyed by dissipation. Paradoxically, the same dissipation, when carefully engineered, can drive a system toward robust entangled steady states.…

We show that absorbing state phase transitions where the absorbing state itself exhibits long-range phase coherence can lead to critical behavior distinct from directed percolation. To do this, we investigate a simple, purely dissipative…

Quantum Physics · Physics 2025-07-18 Matthew Wampler , Nigel R. Cooper

Nature is governed by precise physical laws, which can inspire the discovery of new computer-run simulation algorithms. Thermal states are the most ubiquitous for they are the equilibrium states of matter. Simulating thermal states of…

Quantum Physics · Physics 2023-04-13 Oles Shtanko , Ramis Movassagh

NISQ era devices suffer from a number of challenges like limited qubit connectivity, short coherence times and sizable gate error rates. Thus, quantum algorithms are desired that require shallow circuit depths and low qubit counts to take…

Quantum computers have been widely speculated to offer significant advantages in obtaining the ground state of difficult Hamiltonian in chemistry and physics. In this work, we first propose a Lyapunov control-inspired strategy to accelerate…

Quantum Physics · Physics 2022-12-21 Yu-Cheng Chen , Yu-Qin Chen , Alice Hu , Chang-Yu Hsieh , Shengyu Zhang

Discrete combinatorial optimization consists in finding the optimal configuration that minimizes a given discrete objective function. An interpretation of such a function as the energy of a classical system allows us to reduce the…

Quantum Physics · Physics 2015-06-22 Sergio Boixo , Gerardo Ortiz , Rolando Somma

We propose applying the adiabatic algorithm to prepare high-energy eigenstates of integrable models on a quantum computer. We first review the standard adiabatic algorithm to prepare ground states in each magnetization sector of the…

Quantum Physics · Physics 2026-03-18 Maximilian Lutz , Lorenzo Piroli , Georgios Styliaris , J. Ignacio Cirac

Variational methods have offered controllable and powerful tools for capturing many-body quantum physics for decades. The recent introduction of expressive neural network quantum states has enabled the accurate representation of a broad…

Quantum Physics · Physics 2025-10-20 Matija Medvidović , Alev Orfi , Juan Carrasquilla , Dries Sels

Preparing the ground state of a system is an important task in physics. We propose a quantum algorithm for preparing the ground state of a physical system that can be simulated on a quantum computer. The system is coupled to an ancillary…

Quantum Physics · Physics 2018-05-14 Hefeng Wang

We discuss the possibility of preparing highly entangled states by simply cooling atoms into the ground state of an applied interaction Hamiltonian. As in laser sideband cooling, we take advantage of a relatively large detuning of the…

Quantum Physics · Physics 2015-05-13 Giovanni Vacanti , Almut Beige