Simulation of the spin-boson model with superconducting phase qubit coupled to a transmission line

TL;DR

This paper proposes a superconducting circuit-based simulation of the spin-boson model to detect quantum Kosterlitz-Thouless phase transition, utilizing a phase qubit coupled to a transmission line, with parameters estimated via numerical methods.

Contribution

It introduces a feasible scheme to simulate the spin-boson model with superconducting circuits for observing quantum phase transitions.

Findings

Quantum KT transition can be detected through qubit state tomography.

Design of a superconducting circuit for spin-boson simulation.

Estimated experimental parameters using numerical renormalization group.

Abstract

Based on the rapid experimental developments of circuit QED, we propose a feasible scheme to simulate a spin-boson model with the superconducting circuits, which can be used to detect quantum Kosterlitz-Thouless (KT) phase transition. We design the spin-boson model by using a superconducting phase qubit coupled with a semi-infinite transmission line, which is regarded as bosonic reservoir with a continuum spectrum. By tuning the bias current or the coupling capacitance, the quantum KT transition can be directly detected through tomography measurement on the states of the phase qubit. We also estimate the experimental parameters using numerical renormalization group method.