Nonlocal macroscopic quantum tunneling and quantum terahertz electrodynamics in layered superconductors: Theory and simulations

Sergey Savel’ev; A. O. Sboychakov; A. L. Rakhmanov; Franco Nori

doi:10.1103/PhysRevB.77.014509

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Nonlocal macroscopic quantum tunneling and quantum terahertz electrodynamics in layered superconductors: Theory and simulations

Sergey Savel’ev, A. O. Sboychakov, A. L. Rakhmanov, Franco Nori

DOI 10.1103/PhysRevB.77.014509 · Physical Review B

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Abstract

We derive a quantum field theory of Josephson plasma waves (JPWs) in layered superconductors, which describes two types of interacting JPW bosonic quanta (one heavy and one lighter). We propose a mechanism of enhancement of macroscopic quantum tunneling (MQT) in stacks of intrinsic Josephson junctions. Due to the long-range interaction between junctions in layered superconductors, the calculated MQT escape rate Γ has a nonlinear dependence on the number of junctions in the stack. We develop a numerical procedure, based on quantum field tunneling theory, to calculate Γ for the stack of Josephson junctions. We also propose a simple analytical formula to estimate the MQT escape rate. Moreover, we demonstrate that the direct analogy between fluxon tunneling and tunneling of a quantum particle fails even for very thin junction stacks (about 1μm for Bi2Sr2CaCu2O8+δ) and a field-theoretical approach is necessary. The theory developed here allows to quantitatively describe striking recent experiments in Bi2Sr2CaCu2O8+δ stacks.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Bi2Sr2CaCu2O8+δ Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown