[INVITED] superconducting artificial atoms towards quantum information processing

Franco Nori, J. Q. You

Yasunobu Nakamura

Kai-I Chu, Xiao-Cheng Lu, Kuan-Hsun Chiang +5 more

Recent progresses in Josephson-junction-based superconducting circuits have propelled quantum information processing forward. However, the lack of a metastable state in most superconducting artificial atoms hinders the development of photonic quantum memory in this platform. Here we use a single superconducting qubit-resonator system to realize a desired Λ -type artificial atom, and to demonstrate slow light with a group velocity of 3.6 km/s and the microwave storage with a memory time extending to several hundred nanoseconds via electromagnetically induced transparency. Our results highlight the potential of achieving microwave quantum memory, promising substantial advancements in quantum information processing within superconducting circuits.

Alexandre Blais

R. McDermott

Frederico Brito, Francisco Rouxinol, M D LaHaye +1 more

Over the past several decades, a rich series of experiments has repeatedly verified the quantum nature of superconducting devices, leading some of these systems to be regarded as artificial atoms. In addition to their application in quantum information processing, these ‘atoms’ provide a test bed for studying quantum mechanics in macroscopic limits. Regarding the last point, we present here a feasible protocol for directly testing time reversal symmetry (TRS) through the verification of the microreversibility principle in a superconducting artificial atom. TRS is a fundamental property of quantum mechanics and is expected to hold if the dynamics of the artificial atom strictly follow the Schrödinger equation. However, this property has yet to be tested in any macroscopic quantum system. In the end, as an application of this work, we outline how the successful implementation of the protocol would provide the first verification of the quantum work fluctuation theorems with superconducting systems.