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We introduce a reinforcement learning algorithm designed to identify the fixed points of a given quantum operation. The method iteratively constructs the unitary transformation that maps the computational basis onto the basis of fixed…

Quantum Physics · Physics 2025-11-25 María Laura Olivera-Atencio , Jesús Casado-Pascual , Denis Lacroix

The use of near-term quantum devices that lack quantum error correction, for addressing quantum chemistry and physics problems, requires hybrid quantum-classical algorithms and techniques. Here we present a process for obtaining the…

Quantum Physics · Physics 2023-08-14 Pejman Jouzdani , Stefan Bringuier

We propose a quantum algorithm for solving the following problem: given the Hamiltonian of a physical system and one of its eigenvalues, how to obtain the corresponding eigenstate? The algorithm is based on the resonance phenomena. For a…

Quantum Physics · Physics 2016-06-01 Hefeng Wang

An adiabatic quantum algorithm is essentially given by three elements: An initial Hamiltonian with known ground state, a problem Hamiltonian whose ground state corresponds to the solution of the given problem and an evolution schedule such…

Quantum Physics · Physics 2019-09-17 Davide Pastorello , Enrico Blanzieri

A quantum state for being an eigenstate of some local Hamiltonian should be constraint by zero energy variance and consequently, the constraint is rather strong that a single eigenstate may uniquely determine the Hamiltonian. For…

Quantum Physics · Physics 2024-12-17 Xu-Dan Xie , Zheng-Yuan Xue , Dan-Bo Zhang

A quantum-mechanical Hamiltonian with a gravitational potential is derived in the framework of local times. This Hamiltonian is the one used by E. H. Lieb (Bull. Amer. Math. Soc. 22(1990), 1-49) in his explanation of stability and…

General Relativity and Quantum Cosmology · Physics 2008-02-03 Hitoshi Kitada

We propose a general-purpose quantum algorithm for preparing ground states of quantum Hamiltonians from a given trial state. The algorithm is based on techniques recently developed in the context of solving the quantum linear systems…

Quantum Physics · Physics 2018-02-05 Yimin Ge , Jordi Tura , J. Ignacio Cirac

The presence of symmetries, be they discrete or continuous, in a physical system typically leads to a reduction in the problem to be solved. Here we report that neither translational invariance nor rotational invariance reduce the…

Quantum Physics · Physics 2008-07-24 Alastair Kay

We study the efficiency of algorithms simulating a system evolving with Hamiltonian $H=\sum_{j=1}^m H_j$. We consider high order splitting methods that play a key role in quantum Hamiltonian simulation. We obtain upper bounds on the number…

Quantum Physics · Physics 2010-10-12 Anargyros Papageorgiou , Chi Zhang

We derive out a complete series expression of Hamiltonian eigenvalues without any approximation and cut in the general quantum systems based on Wang's formal framework \cite{wang1}. In particular, we then propose a calculating approach of…

Quantum Physics · Physics 2009-11-12 Zhou Li , An Min Wang

Fast-forwarding refers to the ability to simulate a system of time $t$ using significantly fewer than $t$ queries or circuit depth. While various Hamiltonian systems are known to circumvent the no fast-forwarding theorem, analogous results…

Quantum Physics · Physics 2026-05-25 Zhong-Xia Shang , Dong An , Changpeng Shao

A central challenge in quantum simulation is to prepare low-energy states of strongly interacting many-body systems. In this work, we study the problem of preparing a quantum state that optimizes a random all-to-all, sparse or dense, spin…

Quantum Physics · Physics 2024-11-06 Joao Basso , Chi-Fang Chen , Alexander M. Dalzell

We present a Hamiltonian quantum computation scheme universal for quantum computation (BQP). Our Hamiltonian is a sum of a polynomial number (in the number of gates L in the quantum circuit) of time-independent, constant-norm, 2-local…

Quantum Physics · Physics 2013-05-30 Daniel Nagaj

The Hamiltonian of a quantum system governs the dynamics of the system via the Schrodinger equation. In this paper, the Hamiltonian is reconstructed in the Pauli basis using measurables on random states forming a time series dataset. The…

Quantum Physics · Physics 2023-05-10 Rishabh Gupta , Raja Selvarajan , Manas Sajjan , Raphael D. Levine , Sabre Kais

We introduce a generalizable framework for learning to identify effective Hamiltonians directly from experimental data in solid-state quantum systems. Our approach is based on a physics-informed neural network architecture that embeds…

Mesoscale and Nanoscale Physics · Physics 2026-03-04 Jarosław Pawłowski , Mateusz Krawczyk

Characterizing the Hamiltonians of continuous-variable (CV) quantum systems is a fundamental challenge laden with difficulties arising from infinite-dimensional Hilbert spaces and unbounded operators. Existing protocols for achieving the…

Quantum Physics · Physics 2025-10-10 Xi Huang , Lixing Zhang , Di Luo

We present a quantum algorithm to prepare the thermal Gibbs state of interacting quantum systems. This algorithm sets a universal upper bound D^alpha on the thermalization time of a quantum system, where D is the system's Hilbert space…

Quantum Physics · Physics 2013-05-29 David Poulin , Pawel Wocjan

Solving the ground state and the ground-state properties of quantum many-body systems is generically a hard task for classical algorithms. For a family of Hamiltonians defined on an $m$-dimensional space of physical parameters, the ground…

Quantum Physics · Physics 2024-08-13 Yanming Che , Clemens Gneiting , Franco Nori

We propose an iterative algorithm to simulate the dynamics generated by any $n$-qubit Hamiltonian. The simulation entails decomposing the unitary time evolution operator $U$ (unitary) into a product of different time-step unitaries. The…

Quantum Physics · Physics 2012-04-09 Ashok Ajoy , Rama Koteswara Rao , Anil Kumar , Pranaw Rungta

We derive in this study a Hamiltonian to solve with certainty the analog quantum search problem analogue to the Grover algorithm. The general form of the initial state is considered. Since the evaluation of the measuring time for finding…

Quantum Physics · Physics 2007-05-23 Jin-Yuan Hsieh , Che-Ming Li , Der-San Chuu