TY - JOUR T1 - On-demand indistinguishable single photons from an efficient and pure source based on a Rydberg ensemble Y1 - 2020 A1 - Dalia P. Ornelas-Huerta A1 - Alexander N. Craddock A1 - Elizabeth A. Goldschmidt A1 - Andrew J. Hachtel A1 - Yidan Wang A1 - P. Bienias A1 - Alexey V. Gorshkov A1 - Steve L. Rolston A1 - James V. Porto AB -

Single photons coupled to atomic systems have shown to be a promising platform for developing quantum technologies. Yet a bright on-demand, highly pure and highly indistinguishable single-photon source compatible with atomic platforms is lacking. In this work, we demonstrate such a source based on a strongly interacting Rydberg system. The large optical nonlinearities in a blockaded Rydberg ensemble convert coherent light into a single-collective excitation that can be coherently retrieved as a quantum field. We observe a single-transverse-mode efficiency up to 0.18(2), g(2)=2.0(1.5)×10−4, and indistinguishability of 0.982(7), making this system promising for scalable quantum information applications. Accounting for losses, we infer a generation probability up to 0.40(4). Furthermore, we investigate the effects of contaminant Rydberg excitations on the source efficiency. Finally, we introduce metrics to benchmark the performance of on-demand single-photon sources. 

UR - https://arxiv.org/abs/2003.02202 ER - TY - JOUR T1 - Heisenberg-Scaling Measurement Protocol for Analytic Functions with Quantum Sensor Networks JF - Phys. Rev. A Y1 - 2019 A1 - Kevin Qian A1 - Zachary Eldredge A1 - Wenchao Ge A1 - Guido Pagano A1 - Christopher Monroe A1 - James V. Porto A1 - Alexey V. Gorshkov AB -

We generalize past work on quantum sensor networks to show that, for d input parameters, entanglement can yield a factor O(d) improvement in mean squared error when estimating an analytic function of these parameters. We show that the protocol is optimal for qubit sensors, and conjecture an optimal protocol for photons passing through interferometers. Our protocol is also applicable to continuous variable measurements, such as one quadrature of a field operator. We outline a few potential applications, including calibration of laser operations in trapped ion quantum computing.

VL - 100 UR - https://arxiv.org/abs/1901.09042 CP - 042304 U5 - https://doi.org/10.1103/PhysRevA.100.042304 ER - TY - JOUR T1 - Dark state optical lattice with sub-wavelength spatial structure JF - Phys. Rev. Lett. Y1 - 2018 A1 - Yang Wang A1 - Sarthak Subhankar A1 - Przemyslaw Bienias A1 - Mateusz Lacki A1 - Tsz-Chun Tsui A1 - Mikhail A. Baranov A1 - Alexey V. Gorshkov A1 - Peter Zoller A1 - James V. Porto A1 - Steven L. Rolston AB -

We report on the experimental realization of a conservative optical lattice for cold atoms with a subwavelength spatial structure. The potential is based on the nonlinear optical response of three-level atoms in laser-dressed dark states, which is not constrained by the diffraction limit of the light generating the potential. The lattice consists of a one-dimensional array of ultranarrow barriers with widths less than 10 nm, well below the wavelength of the lattice light, physically realizing a Kronig-Penney potential. We study the band structure and dissipation of this lattice and find good agreement with theoretical predictions. Even on resonance, the observed lifetimes of atoms trapped in the lattice are as long as 44 ms, nearly 105times the excited state lifetime, and could be further improved with more laser intensity. The potential is readily generalizable to higher dimensions and different geometries, allowing, for example, nearly perfect box traps, narrow tunnel junctions for atomtronics applications, and dynamically generated lattices with subwavelength spacings.

VL - 120 U4 - 083601 UR - https://link.aps.org/doi/10.1103/PhysRevLett.120.083601 U5 - 10.1103/PhysRevLett.120.083601 ER - TY - JOUR T1 - Dissipation induced dipole blockade and anti-blockade in driven Rydberg systems JF - Phys. Rev. A Y1 - 2018 A1 - Jeremy T. Young A1 - Thomas Boulier A1 - Eric Magnan A1 - Elizabeth A. Goldschmidt A1 - Ryan M. Wilson A1 - Steven L. Rolston A1 - James V. Porto A1 - Alexey V. Gorshkov AB -

We study theoretically and experimentally the competing blockade and antiblockade effects induced by spontaneously generated contaminant Rydberg atoms in driven Rydberg systems. These contaminant atoms provide a source of strong dipole-dipole interactions and play a crucial role in the system's behavior. We study this problem theoretically using two different approaches. The first is a cumulant expansion approximation, in which we ignore third-order and higher connected correlations. Using this approach for the case of resonant drive, a many-body blockade radius picture arises, and we find qualitative agreement with previous experimental results. We further predict that as the atomic density is increased, the Rydberg population's dependence on Rabi frequency will transition from quadratic to linear dependence at lower Rabi frequencies. We study this behavior experimentally by observing this crossover at two different atomic densities. We confirm that the larger density system has a smaller crossover Rabi frequency than the smaller density system. The second theoretical approach is a set of phenomenological inhomogeneous rate equations. We compare the results of our rate-equation model to the experimental observations [E. A. Goldschmidt et al.Phys. Rev. Lett. 116, 113001 (2016)] and find that these rate equations provide quantitatively good scaling behavior of the steady-state Rydberg population for both resonant and off-resonant drives.

VL - 97 U4 - 023424 UR - https://link.aps.org/doi/10.1103/PhysRevA.97.023424 U5 - 10.1103/PhysRevA.97.023424 ER -