Entangling microwaves with light

Abstract

Quantum entanglement is a key resource in currently developed quantum technologies. Sharing this fragile property between superconducting microwave circuits and optical or atomic systems would enable new functionalities, but this has been hindered by an energy scale mismatch of >10 4 and the resulting mutually imposed loss and noise. In this work, we created and verified entanglement between microwave and optical fields in a millikelvin environment. Using an optically pulsed superconducting electro-optical device, we show entanglement between propagating microwave and optical fields in the continuous variable domain. This achievement not only paves the way for entanglement between superconducting circuits and telecom wavelength light, but also has wide-ranging implications for hybrid quantum networks in the context of modularization, scaling, sensing, and cross-platform verification.

Ultrafast All-Optical Modulation and Efficient Third-Harmonic Generation in Two-Dimensional Perovskite Heterostructures

“…where n 1 and n 3 are the complex refractive indices at the fundamental and TH wavelengths, respectively, χ (3) is the third-order NLO susceptibility of the sample at the pump wavelength, α is the absorption coefficient at the TH wavelength, t is the sample thickness, and k 1 and k 3 are the wavenumbers for the fundamental and harmonic beams. The THG efficiency (η = I 3 /I 1 ) at 1650 nm was estimated to be 2 × 10 −5 , and the corresponding third-order NLO susceptibility χ (3) was calculated to be 3.54 × 10 −18 m 2 /V 2 (see Note 2 of the Supporting Information).…”

“…The fabrication process of 2D (PEA) 2 PbI 4 (n = 1), (PEA) 2 (MA) 2 Pb 3 I 10 (n = 3), and (PEA) 2 PbI 4 /(PEA) 2 -(MA) 2 Pb 3 I 10 heterostructure; characteristics of 2D heterostructure film, including X-ray diffraction patterns and AFM images; SEM images of the sample crosssection; linear absorption spectra of the heterostructure from 450 to 2800 nm; TH emission images captured by a CCD camera; FDTD simulation data and model; THG and FHG spectra of the heterostructure at λ pump = 1950 nm; list of η and χ (3)…”

“…Ultrafast all-optical modulation and efficient frequency conversion are highly required for a wide range of applications, including optical communication, microwave photonics, and quantum computing. − The optical modulation can be realized by the light–matter interactions via the electro-optic, acousto-optic, magneto-optic, thermo-optic, and mechano-optic effects, respectively. However, with the arrival of the 5G high-capacity information society, the optical modulators face challenges with the ever-increasing demands for modulation speed and bandwidth. , The all-optical modulation by controlling light with light can offer intrinsic advantages in terms of the operating speed and bandwidth, which is essential for ultrafast, broadband, and cost-effective optical signal processing .…”

Cavity magnomechanics: from classical to quantum

“…Under these conditions, if by further coupling the magnon mode to a microwave cavity via the beam-splitter interaction [14,15] (forming an extended microwave cavity-OMM system, figure 14(c)), the above generated optomagnonic entanglement [37] can then be distributed to the microwave cavity, yielding stationary microwave-optics entanglement [151]. The microwave-optics entanglement finds particularly important applications in building a hybrid quantum network [157]. Employing the microwave cavity-OMM system, an entanglement transfer scheme has been suggested to entangle two microwave fields [158].…”

Optical-Microwave Entanglement Paves the Way for Distributed Quantum Computation

“…[16] Nowadays, generating Bell states or the EPR state in the optical regime is more or less a lab routine. [17] Remarkably, in a recent work of Fink's group at the Institute of Science and Technology Austria, entangled pairs of optical photons at about 193 THz and microwave photons at about 9 GHz, with an energy gap of four orders of magnitude between them, has been successfully prepared [18] and verified in the continuous-variable domain. Such optical-microwave entanglement provides an elegant solution for a quantum network based on supercon-ducting circuits, in which distant superconducting qubits can communicate with each other by optical channels using this teleportation-based protocol: The role of particle A of Fig.…”