Enhancing Quantum Coupling

Daniel Lombardo, Jason Twamley

The quantum coupling of spatially distant spins via optical photons using cavity quantum electrodynamic (cQED) methods has proved experimentally challenging due to the large spin-photon coupling strengths required. To achieve such coupling strengths using traditional cQED methods requires either individual spins and ultra-small cavities or an ensemble of identical spins coupled to larger cavities. In this work we describe a method to couple distant spins via the collective enhanced coupling to a large ensemble ∼ N, of degenerate optical Whispering Gallery Modes (WGM) in a spherical resonator where the spins are spatially located at the antipodes. The setup can be scaled-up to build 1D, 2D and 3D cQED lattices to enable quantum simulation or computing.

Shabina Jamee Modi, Archana R. Panhalkar, Natasha Martin +3 more

With this research, the design and performance of quantum programs will be enhanced by investigating the higher mathematical concepts that underlie quantum computers. The goals of the study also include better error correction and the creation of a more insightful perspective of quantum coupling as well as easier construction of quantum circuits through the integration of the complex theories such as group theory, topology, and operator theory. It demonstrates the way these mathematical infrastructure may contribute significantly to the performance of algorithms and fault tolerance via the analysis of theory and case studies. Moreover, the findings indicate the value of advanced mathematics in overcoming the existing issues and make room to more stable and scalable quantum computing solutions.

Kristina Bodiroga, Jacob Ewaniuk, Andrew N. Wakileh +7 more

Chiral quantum light-matter interfaces, where the internal spin state of a quantum emitter determines the direction in which it emits, are essential building blocks of non-reciprocal quantum devices, deterministic quantum logical gates and entanglement generation protocols. Yet, a chiral quantum interface that operates at telecom wavelengths, and is compatible with telecommunication infrastructure and silicon photonics, does not yet exist. Here, we report on an integrated chiral quantum interface in the original telecom band (1260-1360 nm), created by interfacing InAs quantum dots with a waveguide-coupled InP microdisk. We tune the quantum dot transitions through the photonic cavity using a strong magnetic field, observing a peak cavity enhancement of 3.3 and an emission directionality of 0.985, demonstrating the near-ideal chiral quantum coupling required for quantum information processing on integrated photonic devices.

Xin Xie, Bowen Kang, Huatian Hu +7 more

) exhibit sharp 4f-4f transitions that are highly sensitive to dipole-dipole interactions (DDIs), yet the intrinsic short-range of DDIs restricts their application in long-distance quantum coupling. Here, we demonstrate a plasmonic nanocavity pair that simultaneously couples to upconversion nanoparticles (UCNPs) and quantum dots (QDs), enabling enhanced emission and inter-emitter interaction. The combined effects of Purcell enhancement and surface plasmon polariton (SPP) propagation extend the DDI-mediated energy transfer over a record distance exceeding 7.5 μm, 2 orders of magnitude longer than conventional Förster resonance systems. Moreover, the polarization-controlled SPP propagation directs the in-plane energy redistribution, achieving anisotropic and tunable coupling. This work establishes a viable route toward controllable, long-range DDIs among rare-earth emitters, advancing integrated quantum photonic architectures.