The Cooper Pair Pump as a Quantized Current Source

TL;DR

This paper proposes a topologically-based Cooper Pair Pump that can serve as a highly accurate, quantized current source for metrological standards, leveraging the Chern index for charge quantization.

Contribution

It introduces a novel topological approach to charge quantization in Cooper Pair Pumps using the Hamiltonian's ground state properties over a 3D parameter space.

Findings

Charge quantization is achieved via topological properties.

The pumped charge converges rapidly to a quantized value.

The method is promising for a metrological current standard.

Abstract

A new charge quantization in a phase-polarized Cooper Pair Pump (CPP) is proposed, based on the topological properties of its Hamiltonian ground state over a three-dimensional parameter space $\mathbb{P}$. The charge is quantized using a set of path in $\mathbb{P}$ covering the surface of a torus, and is a multiple of the integer Chern index $c_1$ of this surface. This quantization is asymptotic but the pumped charge converges rapidly to the quantized value with the increase in the path frequency. The topological nature of the current makes this CPP implementation an excellent candidate for a metrological current standard.