Observation of Floquet states in a strongly driven artificial atom

  1. Chunqing Deng,
  2. Jean-Luc Orgiazzi,
  3. Feiruo Shen,
  4. Sahel Ashhab,
  5. and Adrian Lupascu
We present experiments on the driven dynamics of a two-level superconducting artificial atom. The driving strength reaches 4.78 GHz, significantly exceeding the transition frequency
of 2.288 GHz. The observed dynamics is described in terms of quasienergies and quasienergy states, in agreement with Floquet theory. In addition, we observe the role of pulse shaping in the dynamics, as determined by non-adiabatic transitions between Floquet states, and we implement subnanosecond single-qubit operations. These results pave the way to quantum control using strong driving with applications in quantum technologies.

Hybrid quantum circuits: Superconducting circuits interacting with other quantum systems

  1. Ze-Liang Xiang,
  2. Sahel Ashhab,
  3. J. Q. You,
  4. and Franco Nori
Hybrid quantum circuits combine two or more physical systems, with the goal of harnessing the advantages and strengths of the different systems in order to better explore new phenomena
and potentially bring about novel quantum technologies. This article presents a brief overview of the progress achieved so far in the field of hybrid circuits involving atoms, spins and solid-state devices (including superconducting and nanomechanical systems). We discuss how these circuits combine elements from atomic physics, quantum optics, condensed matter physics, and nanoscience, and we present different possible approaches for integrating various systems into a single circuit. In particular, hybrid quantum circuits can be fabricated on a chip, facilitating their future scalability, which is crucial for building future quantum technologies, including quantum detectors, simulators and computers.

Implementing general measurements on linear optical and solid-state qubits

  1. Yukihiro Ota,
  2. Sahel Ashhab,
  3. and Franco Nori
We show a systematic construction for implementing general measurements on a single qubit, including both strong (or projection) and weak measurements. We mainly focus on linear optical
qubits. The present approach is composed of simple and feasible elements, i.e., beam splitters, wave plates, and polarizing beam splitters. We show how the parameters characterizing the measurement operators are controlled by the linear optical elements. We also propose a method for the implementation of general measurements in solid-state qubits.