Quantum algorithms for open lattice field theory

Journal Article · Thu Nov 18 00:00:00 EST 2021 · Phys.Rev.A

DOI:https://doi.org/10.1103/PhysRevA.104.052420· OSTI ID:1834172

Hubisz, Jay ^[1]; Sambasivam, Bharath ^[1]; Unmuth-Yockey, Judah ^[2]

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1. Syracuse U.
2. Syracuse U.; Fermilab

Certain aspects of some unitary quantum systems are well described by evolution via a non-Hermitian effective Hamiltonian, as in the Wigner-Weisskopf theory for spontaneous decay. Conversely, any non-Hermitian Hamiltonian evolution can be accommodated in a corresponding unitary system $+$ environment model via a generalization of Wigner-Weisskopf theory. This demonstrates the physical relevance of novel features such as exceptional points in quantum dynamics, and opens up avenues for studying many-body systems in the complex plane of coupling constants. In the case of lattice field theory, sparsity lends these channels the promise of efficient simulation on standardized quantum hardware. We thus consider quantum operations that correspond to Suzuki-Lie-Trotter approximation of lattice field theories undergoing nonunitary time evolution, with potential applicability to studies of spin or gauge models at finite chemical potential, with topological terms, to quantum phase transitions—a range of models with sign problems. We develop non-Hermitian quantum circuits and explore their promise on a benchmark, the quantum one-dimensional Ising model with complex longitudinal magnetic field, showing that observables can probe the Lee-Yang edge singularity. The development of attractors past critical points in the space of complex couplings indicates a potential for study on near-term noisy hardware.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Syracuse U.
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-07CH11359; SC0009998
• OSTI ID: 1834172
• Alternate ID(s): OSTI ID: 1905122
• Report Number(s): FERMILAB-PUB-20-660-T; oai:inspirehep.net:1835721; arXiv:2012.05257
• Journal Information: Phys.Rev.A, Journal Name: Phys.Rev.A Journal Issue: 5 Vol. 104
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Effective field theory
Lattice field theory
Open quantum systems
Quantum algorithms
Quantum criticality
Quantum master equation
Spin lattice models
effective field theory
lattice field theory
open quantum systems
quantum algorithms
quantum criticality
quantum master equation
spin lattice models