Josephson nanocircuit in the presence of linear quantum noise

TL;DR

This paper derives an effective Hamiltonian for a charge-Josephson qubit considering environmental effects without phenomenological assumptions, aiding the understanding of noise impacts in quantum circuits.

Contribution

It provides a first-principles derivation of the Hamiltonian for Josephson qubits in noisy environments, avoiding phenomenological counterterms.

Findings

Energy renormalizations due to environment are derived explicitly.

The approach can be applied to multiqubit systems.

Insights into geometric quantum computation are discussed.

Abstract

We derive the effective hamiltonian for a charge-Josephson qubit in a circuit with no use of phenomenological arguments, showing how energy renormalizations induced by the environment appear with no need of phenomenological counterterms. This analysis may be important for multiqubit systems and geometric quantum computation.