Tunable directional photon scattering from a pair of superconducting qubits.

The ability to control the direction of scattered light is crucial to provide flexibility and scalability for a wide range of on-chip applications, such as integrated photonics, quantum information processing, and nonlinear optics. Tunable directionality can be achieved by applying external magnetic fields that modify optical selection rules, by using nonlinear effects, or interactions with vibrations. However, these approaches are less suitable to control microwave photon propagation inside integrated superconducting quantum devices.

Publisher Correction: Converting microwave and telecom photons with a silicon photonic nanomechanical interface.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Converting microwave and telecom photons with a silicon photonic nanomechanical interface.

Practical quantum networks require low-loss and noise-resilient optical interconnects as well as non-Gaussian resources for entanglement distillation and distributed quantum computation. The latter could be provided by superconducting circuits but existing solutions to interface the microwave and optical domains lack either scalability or efficiency, and in most cases the conversion noise is not known. In this work we utilize the unique opportunities of silicon photonics, cavity optomechanics and superconducting circuits to demonstrate a fully integrated, coherent transducer interfacing the microwave X and the telecom S bands with a total (internal) bidirectional transduction efficiency of 1.

Stationary entangled radiation from micromechanical motion.

Mechanical systems facilitate the development of a hybrid quantum technology comprising electrical, optical, atomic and acoustic degrees of freedom, and entanglement is essential to realize quantum-enabled devices. Continuous-variable entangled fields-known as Einstein-Podolsky-Rosen (EPR) states-are spatially separated two-mode squeezed states that can be used for quantum teleportation and quantum communication. In the optical domain, EPR states are typically generated using nondegenerate optical amplifiers, and at microwave frequencies Josephson circuits can serve as a nonlinear medium.

Libration of Strongly-Oriented Polar Molecules inside a Superfluid.

We study a polar molecule immersed in a superfluid environment, such as a helium nanodroplet or a Bose-Einstein condensate, in the presence of a strong electrostatic field. We show that coupling of the molecular pendular motion, induced by the field, to the fluctuating bath leads to formation of pendulons-spherical harmonic librators dressed by a field of many-particle excitations. We study the behavior of the pendulon in a broad range of molecule-bath and molecule-field interaction strengths, and reveal that its spectrum features a series of instabilities which are absent in the field-free case of the angulon quasiparticle.