Anti-$$\mathscr{PT}$$-symmetric qubit: Decoherence and entanglement entropy

Journal Article · Mon Feb 07 00:00:00 EST 2022 · Physical Review A

DOI:https://doi.org/10.1103/physreva.105.022404· OSTI ID:1992249

Cen, Julia  ^[1]; Saxena, Avadh  ^[1]

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1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States). Theoretical Division

We investigate the dynamics of a general two-level based anti-parity-time (anti-$$\mathscr{PT}$$)-symmetric qubit and study its decoherence as well as entanglement entropy properties. We compare our findings with that of the corresponding parity-time ($$\mathscr{PT}$$)-symmetric and Hermitian qubits. To begin, we consider the time-dependent Dyson map to find the exact analytical dynamics for a general non-Hermitian qubit system weakly coupled with a thermal bath for pure dephasing, before specializing it to the case of a general anti-$$\mathscr{PT}$$-symmetric qubit. Basing the comparison under the same coupling strength or increasing the non-Hermiticity, we observe that the decoherence function and entanglement entropy of the anti-$$\mathscr{PT}$$-symmetric qubit decays and grows more slowly, respectively, compared to the $$\mathscr{PT}$$-symmetric and Hermitian qubits. Similarly, the corresponding variance and area of Fisher information are much higher compared to the $$\mathscr{PT}$$-symmetric and Hermitian qubits. These results demonstrate that anti-$$\mathscr{PT}$$-symmetric qubits may be better suited for quantum computing and quantum information processing applications than conventional Hermitian or even $$\mathscr{PT}$$-symmetric qubits.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1992249
• Report Number(s): LA-UR-20-26138; TRN: US2404175
• Journal Information: Physical Review A, Vol. 105, Issue 2; ISSN 2469-9926
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

97 MATHEMATICS AND COMPUTING
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
quantum information processing
continuous variables