Entanglement entropy, decoherence, and quantum phase transitions of a dissipative two-level system

Journal Article · Mon Sep 15 04:00:00 EDT 2008 · Annals of Physics (New York)

DOI:https://doi.org/10.1016/j.aop.2007.12.003· OSTI ID:21163736

The concept of entanglement entropy appears in multiple contexts, from black hole physics to quantum information theory, where it measures the entanglement of quantum states. We investigate the entanglement entropy in a simple model, the spin-boson model, which describes a qubit (two-level system) interacting with a collection of harmonic oscillators that models the environment responsible for decoherence and dissipation. The entanglement entropy allows to make a precise unification between entanglement of the spin with its environment, decoherence, and quantum phase transitions. We derive exact analytical results which are confirmed by Numerical Renormalization Group arguments both for an ohmic and a subohmic bosonic bath. The entanglement entropy obeys universal scalings. We make comparisons with entanglement properties in the quantum Ising model and in the Dicke model. We also emphasize the possibility of measuring this entropy using charge qubits subject to electromagnetic noise; such measurements would provide an empirical proof of the existence of entanglement entropy.

• OSTI ID: 21163736
• Journal Information: Annals of Physics (New York), Journal Name: Annals of Physics (New York) Journal Issue: 9 Vol. 323; ISSN 0003-4916; ISSN APNYA6
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BLACK HOLES
BOSONS
ENTROPY
HARMONIC OSCILLATORS
INFORMATION THEORY
ISING MODEL
PHASE TRANSFORMATIONS
QUANTUM DECOHERENCE
QUANTUM ENTANGLEMENT
QUANTUM MECHANICS
QUBITS
RENORMALIZATION
SPIN