Microsecond-lived quantum states in a carbon-based circuit driven by cavity photons

TL;DR

This paper demonstrates that a suspended carbon nanotube double quantum dot embedded in a microwave cavity can achieve quantum coherence times of about 1.3 microseconds, significantly surpassing previous results in carbon and silicon quantum circuits.

Contribution

It introduces a method to manipulate quantum states in a carbon nanotube quantum dot with cavity photons, achieving unprecedented coherence times for carbon-based quantum circuits.

Findings

Quantum coherence times of ~1.3 microseconds achieved

Coherence times are two orders of magnitude larger than previous carbon quantum circuits

Coherence times are one order of magnitude larger than silicon quantum dots in similar environments

Abstract

Semiconductor quantum dots are an attractive platform for the realisation of quantum processors. To achieve long-range coupling between them, quantum dots have been integrated into microwave cavities. However, it has been shown that their coherence is then reduced compared to their cavity-free implementations. Here, we manipulate the quantum states of a suspended carbon nanotube double quantum dot with ferromagnetic contacts embedded in a microwave cavity. By performing quantum manipulations via the cavity photons, we demonstrate coherence times of the order of $1.3\mu s$, two orders of magnitude larger than those measured so far in any carbon quantum circuit and one order of magnitude larger than silicon-based quantum dots in comparable environment. This holds promise for carbon as a host material for spin qubits in circuit quantum electrodynamics.