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The computational complexity of simulating quantum many-body systems generally scales exponentially with the number of particles. This enormous computational cost prohibits first principles simulations of many important problems throughout…

Quantum Physics · Physics 2023-05-31 Chao Yin , Andrew Lucas

Quantum computers can be used to address molecular structure, materials science and condensed matter physics problems, which currently stretch the limits of existing high-performance computing resources. Finding exact numerical solutions to…

One of the current major challenges surrounding the use of quantum annealers for solving practical optimization problems is their inability to encode even moderately sized problems---the main reason for this being the rigid layout of their…

Quantum Physics · Physics 2016-10-03 Itay Hen , Marcelo S. Sarandy

We present a real-time quantum Monte Carlo algorithm that simulates the dynamics of open quantum systems by stochastically compressing and evolving the density matrix under both Markovian and non-Markovian master equations. Our algorithm…

Quantum Physics · Physics 2025-09-11 Tong Shen , Daniel A. Lidar

Recent works on quantum algorithms for solving semidefinite optimization (SDO) problems have leveraged a quantum-mechanical interpretation of positive semidefinite matrices to develop methods that obtain quantum speedups with respect to the…

Quantum Physics · Physics 2025-06-06 Brandon Augustino , Giacomo Nannicini , Tamás Terlaky , Luis Zuluaga

Construction of explicit quantum circuits follows the notion of the "standard circuit model" introduced in the solid and profound analysis of elementary gates providing quantum computation. Nevertheless the model is not always optimal (e.g.…

Quantum Physics · Physics 2007-05-23 K. Ch. Chatzisavvas , C. Daskaloyannis , C. P. Panos

The theory of holographic algorithms, which are polynomial time algorithms for certain combinatorial counting problems, yields insight into the hierarchy of complexity classes. In particular, the theory produces algebraic tests for a…

Computational Complexity · Computer Science 2009-04-07 J. M. Landsberg , Jason Morton , Serguei Norine

The negative sign problem in quantum Monte Carlo (QMC) simulations of cluster impurity problems is the major bottleneck in cluster dynamical mean field calculations. In this paper we systematically investigate the dependence of the sign…

Strongly Correlated Electrons · Physics 2015-11-18 Hiroshi Shinaoka , Yusuke Nomura , Silke Biermann , Matthias Troyer , Philipp Werner

Recent works have shown that quantum computers can polynomially speed up certain SAT-solving algorithms even when the number of available qubits is significantly smaller than the number of variables. Here we generalise this approach. We…

Quantum Physics · Physics 2020-02-19 Yimin Ge , Vedran Dunjko

We present a simple, robust and highly efficient method for optimizing all parameters of many-body wave functions in quantum Monte Carlo calculations, applicable to continuum systems and lattice models. Based on a strong zero-variance…

Other Condensed Matter · Physics 2009-11-11 C. J. Umrigar , Julien Toulouse , Claudia Filippi , S. Sorella , R. G. Hennig

It is shown that any two Hamiltonians H(t) and H'(t) of N dimensional quantum systems can be related by means of time-dependent canonical transformations (CT). The dynamical symmetry group of system with Hamiltonian H(t) coincides with the…

Quantum Physics · Physics 2007-05-23 D. A. Trifonov

Quantum computing is a promising technology that harnesses the peculiarities of quantum mechanics to deliver computational speedups for some problems that are intractable to solve on a classical computer. Current generation noisy…

Numerical Analysis · Mathematics 2022-09-16 Daan Camps , Efekan Kökcü , Lindsay Bassman , Wibe A. de Jong , Alexander F. Kemper , Roel Van Beeumen

Quantum Monte Carlo (QMC) is an advanced simulation methodology for studies of manybody quantum systems. In this review, we focus on the electronic structure QMC, i.e., methods relevant for systems described by the electron-ion…

Other Condensed Matter · Physics 2010-08-16 Michal Bajdich , Lubos Mitas

Searches for possible new quantum phases and classifications of quantum phases have been central problems in physics. Yet, they are indeed challenging problems due to the computational difficulties in analyzing quantum many-body systems and…

Quantum Physics · Physics 2011-04-05 Beni Yoshida

NP-hard problems are not believed to be exactly solvable through general polynomial time algorithms. Hybrid quantum-classical algorithms to address such combinatorial problems have been of great interest in the past few years. Such…

Quantum Physics · Physics 2024-01-15 Yagnik Chatterjee , Eric Bourreau , Marko J. Rančić

We propose a novel quantum Monte Carlo method in configuration space, which stochastically samples the contribution from a large secondary space to the effective Hamiltonian in the energy dependent partitioning of L\"owdin. The method…

Chemical Physics · Physics 2015-06-15 Seiichiro Ten-no

Topological quantum computing promises error-resistant quantum computation without active error correction. However, there is a worry that during the process of executing quantum gates by braiding anyons around each other, extra anyonic…

Quantum Physics · Physics 2015-08-05 Chris Cesare , Andrew J. Landahl , Dave Bacon , Steven T. Flammia , Alice Neels

The Local Hamiltonian problem (finding the ground state energy of a quantum system) is known to be QMA-complete. The Local Consistency problem (deciding whether descriptions of small pieces of a quantum system are consistent) is also known…

Quantum Physics · Physics 2007-12-17 Yi-Kai Liu

In order for quantum computations to be done as efficiently as possible it is important to optimise the number of gates used in the underlying quantum circuits. In this paper we find that many gate optimisation problems for approximately…

Quantum Physics · Physics 2024-08-13 John van de Wetering , Matt Amy

Neural networks has recently attracted much interest as useful representations of quantum many body ground states, which might help address the infamous sign problem. Most attention was directed at their representability properties, while…

Quantum Physics · Physics 2024-11-07 Harel Kol-Namer , Moshe Goldstein