Entangled Images from Four-Wave Mixing

TL;DR: Two-mode quadrature squeezing from four-wave mixing in rubidium vapor exhibits squeezing bandwidth up to 20 MHz and vacuum squeezing down to less than 1 Hz. Different sideband frequencies represent independent sources of squeezing, and group velocity delays impact the correlations in the system.

TL;DR: Multipartite entanglement generation with high-order non-Hermitian exceptional points from dressing-controlled atomic nonlinearity generates multimode entanglement through atomic four-wave mixing and analyzes exceptional points in non-Hermitian systems.

Abstract: In the past couple of decades, there have been significant advances in measuring quantum properties of light, such as quadratures of squeezed light and single-photon counting. Here, we explore whether such tools can be leveraged to probe electronic correlations in the many-body quantum regime. Specifically, we show that it is possible to probe certain spin, charge, and topological orders in an electronic system by measuring the correlation functions of scattered photons. We construct a mapping from the correlators of the scattered photons to those of a correlated insulator, particularly for Mott insulators described by a single-band Fermi-Hubbard model at half filling. We show that frequency filtering before photodetection plays a crucial role in determining this mapping. We find that if the ground state of the insulator is a gapped spin liquid, a photon-pair correlation function, i.e., G ( 2 ) , can detect the presence of anyonic excitations with fractional mutual statistics. Moreover, we show that correlations between electromagnetic quadratures can be used to detect expectation values of static spin chirality operators on both the kagome and triangular lattices, thus being useful in detecting chiral spin liquids. More generally, we show that a series of hitherto unmeasured spin-spin and spin-charge correlation functions of the material can be extracted from photonic correlations. This work opens up access to probe correlated materials, beyond the linear-response paradigm, by detecting quantum properties of scattered light.

TL;DR: Experimental realization of OAM multiplexed four-beam quadrature squeezing using four-wave mixing in rubidium vapor. The degree of squeezing decreases with increasing topological charge.

TL;DR: This work demonstrates entanglement involving the spatial modes of the electromagnetic field carrying orbital angular momentum, which provides a practical route to entangled states that involves many orthogonal quantum states, rather than just two Multi-dimensional entangled states could be of considerable importance in the field of quantum information, enabling, for example, more efficient use of communication channels in quantum cryptography.

TL;DR: The Peres-Horodecki criterion of positivity under partial transpose is studied in the context of separability of bipartite continuous variable states and turns out to be a necessary and sufficient condition for separability.

TL;DR: An inseparability criterion based on the total variance of a pair of Einstein-Podolsky-Rosen type operators is proposed for continuous variable systems and turns out to be a necessary and sufficient condition for inseparability.

TL;DR: In this article, the orbital angular momentum of photons is exploited to achieve multi-dimensional entanglement in higher dimensions, i.e., the state of the electromagnetic field with phase singularities (doughnut modes).