Macroscopic quantum superpositions in superconducting circuits

TL;DR

This paper proposes a method to induce and observe quantum features in macroscopic superconducting circuits by interacting with vacuum fluctuations, revealing a quantum-to-classical transition as pulse length increases.

Contribution

It introduces a novel, simple model showing how classical current pulses can acquire quantum properties through vacuum interactions in superconducting circuits.

Findings

Test current pulses can develop quantum features after vacuum interaction

Vacuum fluctuations can cause breakdown of energy and momentum conservation

Quantum-to-classical transition occurs as pulse length increases

Abstract

A possible route to test whether macroscopic systems can acquire quantum features using superconducting circuits is here presented. It is shown that under general assumptions a classical test current pulse of fixed energy and adjustable length acquires quantum features after interacting with the quantum vacuum of the photon field. Further, it is shown that the mere existence of vacuum fluctuations can lead to the breakdown of energy and momentum conservation, and as the length of the pulse grows with respect to the characteristic size of the quantum system, the test pulse undergoes quantum-to-classical transition. This model differs from previous ones for its simplicity and points towards a new way of creating correlated systems suitable for quantum-based technology.