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Related papers: State preparation and symmetries

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For any local Hamiltonian H, I construct a local CPT map and stopping condition which converges to the ground state subspace of H. Like any ground state preparation algorithm, this algorithm necessarily has exponential run-time in general…

Quantum Physics · Physics 2023-09-25 Toby S. Cubitt

Two-dimensional Projected Entangled Pair States (PEPS) provide a unique framework giving access to detailed entanglement features of correlated (spin or electronic) systems. For a bi-partitioned quantum system, it has been argued that the…

Strongly Correlated Electrons · Physics 2015-06-22 Didier Poilblanc

The variational quantum eigensolver (VQE) is one of the most promising algorithms to find eigenvalues and eigenvectors of a given Hamiltonian on noisy intermediate-scale quantum (NISQ) devices. A particular application is to obtain ground…

Pairwise quantum correlations in the ground state of a N-spins antiferromagnetic chain described by the Heisenberg model with nearest neighbor exchange coupling are investigated. By varying a single coupling between two neighboring sites it…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 P. R. Wells , C. M. Chaves , J. A. e. Castro , Belita Koiller

We propose a new type of Monte Carlo approach in numerical studies of quantum systems. Introducing a probability function which determines whether a state in the vector space survives or not, we can evaluate expectation values of powers of…

Strongly Correlated Electrons · Physics 2009-11-10 Tomo Munehisa , Yasuko Munehisa

Variational algorithms have received significant attention in recent years due to their potential to solve practical problems using noisy intermediate-scale quantum (NISQ) devices. A fundamental step of these algorithms is the evaluation of…

We introduce a new class of generative quantum-neural-network-based models called Quantum Hamiltonian-Based Models (QHBMs). In doing so, we establish a paradigmatic approach for quantum-probabilistic hybrid variational learning, where we…

Quantum Physics · Physics 2019-10-07 Guillaume Verdon , Jacob Marks , Sasha Nanda , Stefan Leichenauer , Jack Hidary

In electronic structure theory, variational methods offer a valuable paradigm for approximating electronic ground states. However, for historical reasons, this principle is mostly restricted to model chemistries in pre-defined fixed basis…

Quantum Physics · Physics 2025-11-17 Fabian Langkabel , Stefan Knecht , Jakob S. Kottmann

In the context of a two-parameter $(\alpha, \beta)$ deformation of the canonical commutation relation leading to nonzero minimal uncertainties in both position and momentum, the harmonic oscillator spectrum and eigenvectors are determined…

Mathematical Physics · Physics 2008-11-26 C. Quesne , V. M. Tkachuk

The spin-1/2 Heisenberg model on the pyrochlore lattice is an iconic frustrated three-dimensional spin system with a rich phase diagram. Besides hosting several ordered phases, the model is debated to possess a spin-liquid ground state when…

Strongly Correlated Electrons · Physics 2021-11-16 Nikita Astrakhantsev , Tom Westerhout , Apoorv Tiwari , Kenny Choo , Ao Chen , Mark H. Fischer , Giuseppe Carleo , Titus Neupert

Time symmetry in quantum mechanics, where the current quantum state is determined jointly by both the past and the future, offers a more comprehensive description of physical phenomena. This symmetry facilitates both forward and backward…

Quantum Physics · Physics 2025-06-13 Shijie Wei , Jingwei Wen , Xiaogang Li , Peijie Chang , Bozhi Wang , Franco Nori , Guilu Long

The Variational Quantum Eigensolver (VQE) is one of the most promising algorithms for current quantum devices. It employs a classical optimizer to iteratively update the parameters of a variational quantum circuit in order to search for the…

Quantum Physics · Physics 2025-11-19 Chenyu Shi , Hao Wang

Entanglement properties of a basic set of eight entangled three particle pure states possessing certain permutation symmetries are studied. They fall into four sets of two entangled states, differing in their patterns of robustness to…

Quantum Physics · Physics 2009-11-07 A. K. Rajagopal , R. W. Rendell

We study the general quantum Hamiltonian that can be realized with two species of mutually interacting degenerate ultracold atoms in a ring-shaped trap, with the options of rotation and an azimuthal lattice. We examine the spectrum and the…

Quantum Gases · Physics 2023-11-28 Tomáš Opatrný , Kunal K. Das

Quantum machine learning for spin and molecular systems faces critical challenges of scarce labeled data and computationally expensive simulations. To address these limitations, we introduce Hamiltonian-Masked Autoencoding (HMAE), a novel…

Quantum Physics · Physics 2025-10-29 Ibne Farabi Shihab , Sanjeda Akter , Anuj Sharma

Variational quantum eigensolver(VQE) typically minimizes energy with hybrid quantum-classical optimization, which aims to find the ground state. Here, we propose a VQE by minimizing energy variance, which is called as variance-VQE(VVQE).…

Quantum Physics · Physics 2020-06-30 Dan-Bo Zhang , Zhan-Hao Yuan , Tao Yin

Generally, the first step in modeling molecular magnets involves obtaining the low-lying eigenstates of a Heisenberg exchange Hamiltonian which conserves total spin and belongs usually to a non-Abelian point group. In quantum chemistry, it…

Chemical Physics · Physics 2012-06-07 Shaon Sahoo , Raghunathan Rajamani , S. Ramasesha , Diptiman Sen

This work describes a method to prepare the quantum state of the Heisenberg spin-1/2 Hamiltonian for the Kagome Lattice in an IBM 16 qubit quantum computer with a fidelity below 1% of the ground state computed via a classical Eigen-solver.…

Quantum Physics · Physics 2023-07-14 Wladimir Silva

We present the variational separability verifier (VSV), which is a novel variational quantum algorithm (VQA) that determines the closest separable state (CSS) of an arbitrary quantum state with respect to the Hilbert-Schmidt distance (HSD).…

Quantum Physics · Physics 2022-12-20 Mirko Consiglio , Tony John George Apollaro , Marcin Wieśniak

A large body of work has demonstrated that parameterized artificial neural networks (ANNs) can efficiently describe ground states of numerous interesting quantum many-body Hamiltonians. However, the standard variational algorithms used to…

Disordered Systems and Neural Networks · Physics 2023-05-17 Tameem Albash , Conor Smith , Quinn Campbell , Andrew D. Baczewski