Path-entangled radiation from kinetic inductance amplifier

TL;DR

This paper demonstrates a kinetic inductance amplifier that efficiently generates stationary path-entangled microwave radiation, advancing quantum communication and sensing technologies with a simplified, superconducting circuit design.

Contribution

It introduces a novel kinetic inductance quantum-limited amplifier capable of producing and distributing entangled microwave states, with a simple theoretical model and practical advantages over traditional Josephson circuits.

Findings

Successfully generated stationary path-entangled microwave radiation.

Verified entanglement experimentally in the microwave domain.

Presented a beam-splitter model to describe entanglement generation.

Abstract

Continuous variable entangled radiation, known as Einstein-Podolsky-Rosen (EPR) states, are spatially separated quantum states with applications ranging from quantum teleportation and communication to quantum sensing. The ability to efficiently generate and harness EPR states is vital for advancements of quantum technologies, particularly in the microwave domain. Here, we introduce a kinetic inductance quantum-limited amplifier that generates stationary path-entangled microwave radiation. Unlike traditional Josephson junction circuits, our design offers simplified fabrication and operational advantages. By generating single-mode squeezed states and distributing them to different ports of a microwave resonator, we deterministically create distributed entangled states at the output of the resonator. In addition to the experimental verification of entanglement, we present a simple theoretical model using a beam-splitter picture to describe the generation of path-entangled states in kinetic inductance superconducting circuits. This work highlights the potential of kinetic inductance parametric amplifiers, as a promising technology, for practical applications such as quantum teleportation, distributed quantum computing, and enhanced quantum sensing. Moreover, it can contribute to foundational tests of quantum mechanics and advances in next-generation quantum information technologies.