The original motivation to build a quantum computer came from Feynman, who imagined a machine capable of simulating generic quantum mechanical systems--a task that is believed to be intractable for classical computers. Such a machine could have far-reaching applications in the simulation of many-body quantum physics in condensed-matter, chemical and high-energy systems. Part of Feynman's challenge was met by Lloyd, who showed how to approximately decompose the time evolution operator of interacting quantum particles into a short sequence of elementary gates, suitable for operation on a quantum computer. However, this left open the problem of how to simulate the equilibrium and static properties of quantum systems. This requires the preparation of ground and Gibbs states on a quantum computer. For classical systems, this problem is solved by the ubiquitous Metropolis algorithm, a method that has basically acquired a monopoly on the simulation of interacting particles. Here we demonstrate how to implement a quantum version of the Metropolis algorithm. This algorithm permits sampling directly from the eigenstates of the Hamiltonian, and thus evades the sign problem present in classical simulations. A small-scale implementation of this algorithm should be achievable with today's technology.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1038/nature09770 | DOI Listing |
Nano Lett
January 2025
Department of Electrical and Computer Engineering, Northwestern University, Evanston, Illinois 60208, United States.
Metasurfaces supporting narrowband resonances are of significant interest in photonics for molecular sensing, quantum light source engineering, and nonlinear photonics. However, many device architectures rely on large refractive index dielectric materials and lengthy fabrication processes. In this work, we demonstrate quasi-bound states in the continuum (quasi-BICs) using a polymer metasurface exhibiting experimental quality factors of 305 at visible wavelengths.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Laboratoire ICB, UMR-6303 CNRS/uB, Université de Bourgogne, 9 avenue Alain Savary, 21078 Cedex Dijon, France.
We report full quantum-computed average microcanonical, initial state-specific, and canonical cumulative time-delays associated with the O + O scattering, presented as a function of total energy (in relation to an idealized molecular beam experiment) or temperature (for the properties of the gas phase in bulk conditions). We show that these quantities are well-defined and computable, with a temperature-dependent (canonical) time-delay presenting a smooth, monotonic decreasing behavior with temperature, despite an energy-dependent (microcanonical) time-delay of apparent chaotic character. We discuss differences in behavior when considering isotopic variations, O + OO and O + OO, with respect to the reference process O + OO and reveal a greater magnitude of the cumulative time-delay when genuinely reactive events can take place, in the presence of O.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
JNCASR: Jawaharlal Nehru Centre for Advanced Scientific Research, New Chemistry Unit, Jakkur, Bangalore, INDIA.
BiTe, a member of the (Bi2)m(Bi2Te3)n homologous series, possesses natural van der Waals-like heterostructure with a Bi2 bilayer sandwiched between the two [Te-Bi-Te-Bi-Te] quintuple layers. BiTe exhibits both the quantum states of weak topological and topological crystalline insulators, making it a dual topological insulator and a suitable candidate for spintronics, quantum computing and thermoelectrics. Herein, we demonstrate that the chemical bonding in BiTe is to be metavalent, which plays a significant role in the pressure dependent change in the topology of the electronic structure Fermi surface.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Department of Chemistry, The University of Manchester, Manchester M13 9PL, U.K.
The linear vibronic coupling (LVC) model is an approach for approximating how a molecular Hamiltonian changes in response to small changes in molecular geometry. The LVC framework thus has the ability to approximate molecular Hamiltonians at low computational expense but with quality approaching multiconfigurational calculations, when the change in geometry compared to the reference calculation used to parametrize it is small. Here, we show how the LVC approach can be used to project approximate spin Hamiltonians of a solvated lanthanide complex along a room-temperature molecular dynamics trajectory.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Novosibirsk State University, Pirogov str. 1, Novosibirsk 630090, Russian Federation.
Nine metal complexes formed by three symmetric β-diketonates (, acetylacetonate (), 1,1,1,3,3,3-hexafluoro-acetylacetonate (), and 2,2,6,6-tetramethylheptane-3,5-dionate ()) and three metal ions (with three different coordination geometries, , Be - tetrahedral, Cu - square planar, and Pb - "swing" square pyramidal) were investigated. The study combines structural analyses, vibrational spectroscopic techniques, and quantum chemical calculations with the aim of bridging crystal structure, electronic structure, molecular topology, and far-infrared (FIR) spectroscopic characteristics. The effect of intramolecular interactions on the structural, electronic, and spectroscopic features is the center of this study.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!