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We revisit the quantum oscillator model of the electromagnetic field and conclude that, while the nonlocal positive and negative frequency ladder operators generate a photon Fock basis, the Hermitian field operators obtained by second…

Quantum Physics · Physics 2023-12-13 Margaret Hawton

Quantum computing holds immense promise for simulating quantum systems, a critical task for advancing our understanding of complex quantum phenomena. One of the primary goals in this domain is to accurately approximate the ground state of…

Quantum Physics · Physics 2024-11-28 Thilo R. Müller , Manuel Geiger , Christian B. Mendl

The circuit-to-Hamiltonian construction translates dynamics (a quantum circuit and its output) into statics (the groundstate of a circuit Hamiltonian) by explicitly defining a quantum register for a clock. The standard Feynman-Kitaev…

Quantum Physics · Physics 2014-05-20 Nikolas P. Breuckmann , Barbara M. Terhal

We analyze a class of mean-field (MF) lattice-fermion Hamiltonians and construct the corresponding grand-canonical density operator for such system. New terms are introduced, which may be interpreted as local fugacities, molecular fields,…

Strongly Correlated Electrons · Physics 2009-09-01 Jakub Jȩdrak , Jozef Spałek

A version of the configuration interaction method, which has been recently developed to deal with large number of valence electrons, has been used to calculate magnetic dipole and electric quadrupole hyperfine structure constants for a…

Atomic Physics · Physics 2024-02-21 V. A. Dzuba , V. V. Flambaum

Keeping in view the ordering ambiguity that arises due to the presence of position-dependent effective mass in the kinetic energy term of the Hamiltonian, a general scheme for obtaining algebraic solutions of quantum mechanical systems with…

Quantum Physics · Physics 2016-06-29 Naila Amir , Shahid Iqbal

Quantum chemistry has been viewed as one of the potential early applications of quantum computing. Two techniques have been proposed for electronic structure calculations: (i) the variational quantum eigensolver and (ii) the…

Quantum Physics · Physics 2021-04-19 Christina Daniel , Diksha Dhawan , Dominika Zgid , James K. Freericks

We construct local fermionic Hamiltonians with no low-energy trivial states (NLTS), providing a fermionic counterpart to the NLTS theorem. Distinctly from the qubit case, we define trivial states via finite-depth $\textit{fermionic}$…

Quantum Physics · Physics 2023-07-27 Yaroslav Herasymenko , Anurag Anshu , Barbara Terhal , Jonas Helsen

Quantum computers offer the potential to simulate nuclear processes that are classically intractable. With the goal of understanding the necessary quantum resources to realize this potential, we employ state-of-the-art…

Integrable quantum mechanical systems with magnetic fields are constructed in two-dimensional Euclidean space. The integral of motion is assumed to be a first or second order Hermitian operator. Contrary to the case of purely scalar…

Mathematical Physics · Physics 2007-05-23 Josee Berube , Pavel Winternitz

Electronic structure simulation is an anticipated application for quantum computers. Due to high-dimensional quantum entanglement in strongly correlated systems, the quantum resources required to perform such simulations are far beyond the…

Quantum Physics · Physics 2022-01-25 Jie Liu , Zhenyu Li , Jinlong Yang

We have carried out a comparative study of the electronic specific heat and electronic structure of $\alpha$ and $\delta$-plutonium using dynmical mean field theory (DMFT). We use the perturbative T-matrix and fluctuating exchange (T-matrix…

Strongly Correlated Electrons · Physics 2009-11-13 L. V. Pourovskii , G. Kotliar , M. I. Katsnelson , A. I. Lichtenstein

We demonstrate the relation between a global phase of the quantum gate and the layout of energy levels of its effective Hamiltonian required for implementing the gate for minimum time. By an example of the quantum Fourier transform gate for…

Quantum Physics · Physics 2013-12-31 V. P. Shauro , V. E. Zobov

We introduce the fermionized time-dependent Hartree-Fock (fTDHF), a real-time quantum dynamics method for spin-1/2 Hamiltonians following their mapping to fermions via the Jordan-Wigner transformation. fTDHF is formally equivalent to exact…

Strongly Correlated Electrons · Physics 2026-05-25 Rishab Dutta , Marc Illa , Niranjan Govind , Karol Kowalski

Magnetic phase transitions between ordered phases are often understood on the basis of semi-classical spin models. Deviations from the classical description due to the quantum nature of the atomic spins as well as quantum fluctuations are…

Strongly Correlated Electrons · Physics 2026-05-19 Tobias Dannegger , Imre Hagymási , Levente Rózsa , Ulrich Nowak

The general problem of finding the ground state energy of lattice Hamiltonians is known to be very hard, even for a quantum computer. We show here that this is the case even for translationally invariant systems. We also show that a quantum…

Quantum Physics · Physics 2009-11-13 K. G. H. Vollbrecht , J. I. Cirac

The low energy physics of the fractional Hall liquid is described in terms quasiparticles that are qualitatively distinct from electrons. We show, however, that a long-lived electron-like quasiparticle also exists in the excitation…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Jainendra K. Jain , Michael R. Peterson

It is widely believed that mean-field theory is exact for a wide-range of classical long-range interacting systems. Is this also true once quantum fluctuations have been accounted for? As a test case we study the Hamiltonian Mean Field…

Quantum Gases · Physics 2020-02-05 Ryan Plestid , James Lambert

We develop a new version of the superfield Hamiltonian quantization. The main new feature is that the BRST-BFV charge and the gauge fixing Fermion are introduced on equal footing within the sigma model approach, which provides for the…

High Energy Physics - Theory · Physics 2017-08-23 Igor A. Batalin , Peter M. Lavrov

Simulating quantum many-body systems is a highly demanding task since the required resources grow exponentially with the dimension of the system. In the case of fermionic systems, this is even harder since nonlocal interactions emerge due…