Quantum-limited Parametric Amplification with Josephson Circuits in the Regime of Pump Depletion

TL;DR

This paper investigates quantum-limited parametric amplifiers using Josephson circuits, focusing on their dynamic range and fluctuation distributions in the pump depletion regime, crucial for quantum information processing.

Contribution

It provides a detailed analysis of Josephson-based parametric amplifiers operating near the quantum limit, especially in the pump depletion regime, including their scattering properties and fluctuation behavior.

Findings

Analyzed the dynamic range of Josephson parametric amplifiers.

Computed phase-space distributions of mode fluctuations.

Reviewed scattering properties of the amplifiers.

Abstract

Linear parametric amplification is a key operation in information processing. Our interest here is quantum-limited parametric amplification, $i.e.$, amplification of quantum signals while adding the minimum amount of noise allowed by quantum mechanics, which is essential for any viable implementation of quantum information processing. We describe parametric amplifiers based on the dispersive nonlinearity of Josephson junctions driven with appropriate tones playing the role of pumps. We discuss two defining characteristics in the architecture of these amplifiers: the number of modes occupied by the signal, idler and pump waves and the number of independent ports through which these waves enter into the circuit. The scattering properties of these amplifiers is also reviewed. The main focus of this work are the computations of the dynamic range and phase-space distributions of the fluctuations of the modes of the amplifiers.