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We study the computational complexity of the Guided Local Hamiltonian problem: given a local Hamiltonian $H$ together with a classical description of a guiding state that has non-negligible overlap with the ground state of $H$, estimate the…

Quantum Physics · Physics 2026-03-19 Gabriel Waite , Karl Lin , Samuel J Elman , Michael J Bremner

Quantum batteries (QBs) exploit principles of quantum mechanics to accelerate the charging process and aim to achieve optimal energy storage. However, analytical results for investigating these problems remain lacking due to the challenges…

Quantum Physics · Physics 2025-02-11 Hui-Yu Yang , Kun Zhang , Xiao-Hui Wang , Hai-Long Shi

The concept of the {\em half density matrix} is proposed. It unifies the quantum states which are described by density matrices and physical processes which are described by completely positive maps. With the help of the half-density-matrix…

Quantum Physics · Physics 2009-11-06 Sixia Yu

We propose a quantum charging scheme fueled by measurements on ancillary qubits serving as disposable chargers. A stream of identical qubits are sequentially coupled to a quantum battery of $N+1$ levels and measured by projective operations…

Quantum Physics · Physics 2023-07-04 Jia-shun Yan , Jun Jing

The concept of the effective one-electron potentials (OEP) has been useful for many decades in efficient description of electronic structure of chemical systems, especially extended molecular aggregates such as interacting molecules in…

Chemical Physics · Physics 2020-02-04 Bartosz Błasiak , Joanna D. Bednarska , Marta Chołuj , Wojciech Bartkowiak

Quantum computers are now on the brink of outperforming their classical counterparts. One way to demonstrate the advantage of quantum computation is through quantum random sampling performed on quantum computing devices. However, existing…

We investigate optimal control of linear port-Hamiltonian systems with control constraints, in which one aims to perform a state transition with minimal energy supply. Decomposing the state space into dissipative and non-dissipative (i.e.…

Optimization and Control · Mathematics 2021-04-13 Manuel Schaller , Friedrich Philipp , Timm Faulwasser , Karl Worthmann , Bernhard Maschke

The structure of quantum theory assures the discrimination of any possible orthogonal set of states. However, the scenario becomes highly nontrivial in the limited measurement setting and leads to different classes of impossibility, viz.,…

We present a novel approach to the separability problem for Gaussian quantum states of bosonic continuous variable systems. We derive a simplified necessary and sufficient separability criterion for arbitrary Gaussian states of $m$ vs $n$…

Quantum Physics · Physics 2018-02-22 Ludovico Lami , Alessio Serafini , Gerardo Adesso

Quantum states that possess negative conditional von Neumann entropy provide quantum advantage in several information-theoretic protocols including superdense coding, state merging, distributed private randomness distillation and one-way…

Quantum Physics · Physics 2021-07-22 Mahathi Vempati , Nirman Ganguly , Indranil Chakrabarty , Arun K Pati

Non-Hermitian systems generically have complex energies, which may host topological structures, such as links or knots. While there has been great progress in experimentally engineering non-Hermitian models in quantum simulators, it remains…

Quantum Physics · Physics 2023-04-28 Mingming Cao , Kai Li , Wending Zhao , Weixuan Guo , Bingxiag Qi , Xiuying Chang , Zichao Zhou , Yong Xu , Luming Duan

We construct classical algorithms computing an approximation of the ground state energy of an arbitrary $k$-local Hamiltonian acting on $n$ qubits. We first consider the setting where a good ``guiding state'' is available, which is the main…

Quantum Physics · Physics 2025-07-08 François Le Gall

Quantum battery (QB) is the energy storage and extraction device that is governed by the principles of quantum mechanics. Here we propose a three-level Dicke QB and investigate its charging process by considering three quantum optical…

Quantum Physics · Physics 2024-06-28 Dong-Lin Yang , Fang-Mei Yang , Fu-Quan Dou

Quantum work capacitances and maximal asymptotic work/energy ratios are figures of merit characterizing the robustness against noise of work extraction processes in quantum batteries formed by collections of quantum systems. In this paper…

Quantum Physics · Physics 2025-01-31 Salvatore Tirone , Raffaele Salvia , Stefano Chessa , Vittorio Giovannetti

We study the effect of non-Markovianity in the charging process of an open-system quantum battery. We employ a collisional model framework, where the environment is described by a discrete set of ancillary systems and memory effects in the…

Quantum Physics · Physics 2023-05-15 Daniele Morrone , Matteo A. C. Rossi , Andrea Smirne , Marco G. Genoni

One-way quantum computing achieves the full power of quantum computation by performing single particle measurements on some many-body entangled state, known as the resource state. As single particle measurements are relatively easy to…

Quantum Physics · Physics 2013-05-29 Jianxin Chen , Xie Chen , Runyao Duan , Zhengfeng Ji , Bei Zeng

Recently, Halder \emph{et al.} [Phys. Rev. Lett. \textbf{122}, 040403 (2019)] proposed the concept strong nonlocality without entanglement: an orthogonal set of fully product states in multipartite quantum systems that is locally…

Quantum Physics · Physics 2021-10-27 Mao-Sheng Li , Yan-Ling Wang , Fei Shi , Man-Hong Yung

A candidate application for quantum computers is to simulate the low-temperature properties of quantum systems. For this task, there is a well-studied quantum algorithm that performs quantum phase estimation on an initial trial state that…

Quantum Physics · Physics 2024-11-04 Chi-Fang , Chen , Alexander M. Dalzell , Mario Berta , Fernando G. S. L. Brandão , Joel A. Tropp

We analyze a class of entangled states for bipartite $d \otimes d$ systems, with $d$ non-prime. The entanglement of such states is revealed by the construction of canonically associated entanglement witnesses. The structure of the states is…

Quantum Physics · Physics 2009-11-13 M. Piani , C. Mora

The recent resolution of the NLTS Conjecture [ABN22] establishes a prerequisite to the Quantum PCP (QPCP) Conjecture through a novel use of newly-constructed QLDPC codes [LZ22]. Even with NLTS now solved, there remain many independent and…

Quantum Physics · Physics 2024-06-12 Nolan J. Coble , Matthew Coudron , Jon Nelson , Seyed Sajjad Nezhadi
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