Enhanced cooperativity for quantum-nondemolition-measurement--induced spin squeezing of atoms coupled to a nanophotonic waveguide

Abstract

We study the enhancement of cooperativity in the atom-light interface near a nanophotonic waveguide for application to quantum nondemolition (QND) measurement of atomic spins. Here the cooperativity per atom is determined by the ratio between the measurement strength and the decoherence rate. Counterintuitively, we find that by placing the atoms at an azimuthal position where the guided probe mode has the lowest intensity, we increase the cooperativity. This arises because the QND measurement strength depends on the interference between the probe and scattered light guided into an orthogonal polarization mode, while the decoherence rate depends on the local intensity of the probe. Thus, by proper choice of geometry, the ratio of good to bad scattering can be strongly enhanced for highly anisotropic modes. We apply this to study spin squeezing resulting from QND measurement of spin projection noise via the Faraday effect in two nanophotonic geometries, a cylindrical nanofiber and a square waveguide. We find that, with about 2500 atoms and using realistic experimental parameters, $\sim 6.3$ and $\sim 13$ dB of squeezing can be achieved on the nanofiber and square waveguide, respectively.

8 pages + 2 pages appendix with 7 figures. To appear on Phys. Rev. A

References in corpus (17)

• Chiral Quantum Optics
• Entangled Photon Pairs from Semiconductor Quantum Dots
• A Straightforward Introduction to Continuous Quantum Measurement
• Exponential improvement in photon storage fidelities using subradiance and "selective radiance" in atomic arrays
• Deterministic Generation of a Cluster State of Entangled Photons
• Super-radiance reveals infinite-range dipole interactions through a nanofiber
• Demonstration of a memory for tightly guided light in an optical nanofiber
• Photonic tensor networks produced by a single quantum emitter
• Optically generated 2-dimensional photonic cluster state from coupled quantum dots
• Spin squeezing of a cold atomic ensemble with the nuclear spin of one-half
• Nonlinear pi phase shift for single fiber-guided photons interacting with a single atom
• Storage of fiber-guided light in a nanofiber-trapped ensemble of cold atoms
• Quantum computing by optical control of electron spins
• Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice
• Spin squeezing of atomic ensembles by multi-colour quantum non-demolition measurements
• Dynamics of trapped atoms around an optical nanofiber probed through polarimetry
• Internal Spin Control, Squeezing and Decoherence in Ensembles of Alkali Atomic Spins

Cited by in corpus (5)

• Photon transport mediated by an atomic chain trapped along a photonic crystal waveguide
• Squeezing the angular momentum of an ensemble of complex multi-level atoms
• Characterization of Suspended Membrane Waveguides towards a Photonic Atom Trap Integrated Platform
• Measurement-Induced Entanglement Phase Transition in Free Fermion Systems
• Demonstration of a MOT in a Sub-Millimeter Membrane Hole