Cavity-Based Single Atom Preparation and High-Fidelity Hyperfine State Readout

Gehr, Roger; Volz, Jürgen; Dubois, Guilhem; Steinmetz, Tilo; Colombe, Yves; Lev, Benjamin; Long, Romain; Estève, Jérôme; Reichel, Jakob

doi:10.1103/physrevlett.104.203602

Cited by 125 publications

(104 citation statements)

References 21 publications

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“…Both limitations will be removed in the near future by means of an asymmetric cavity with a lower loss rate. Other types of resonators with smaller mode volumes like microtoroids [28] or fibre resonators [29] could allow one to generate squeezed light on an atom chip. Using artificial atoms like quantum dots in microcavities [18] would lead to larger and fixed atom-cavity couplings.…”

Section: Figmentioning

confidence: 99%

Observation of squeezed light from one atom excited with two photons

Ourjoumtsev

Kubanek

Koch

et al. 2011

Nature

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Single quantum emitters like atoms are wellknown as non-classical light sources which can produce photons one by one at given times [1], with reduced intensity noise. However, the light field emitted by a single atom can exhibit much richer dynamics. A prominent example is the predicted[2] ability for a single atom to produce quadrature-squeezed light [3], with sub-shotnoise amplitude or phase fluctuations. It has long been foreseen, though, that such squeezing would be "at least an order of magnitude more difficult" to observe than the emission of single photons [4]. Squeezed beams have been generated using macroscopic and mesoscopic media down to a few tens of atoms [5], but despite experimental efforts [6][7][8], single-atom squeezing has so far escaped observation. Here we generate squeezed light with a single atom in a highfinesse optical resonator. The strong coupling of the atom to the cavity field induces a genuine quantum mechanical nonlinearity [9], several orders of magnitude larger than for usual macroscopic media [10][11][12]. This produces observable quadrature squeezing [13][14][15] with an excitation beam containing on average only two photons per system lifetime. In sharp contrast to the emission of single photons [16], the squeezed light stems from the quantum coherence of photon pairs emitted from the system [17]. The ability of a single atom to induce strong coherent interactions between propagating photons opens up new perspectives for photonic quantum logic with single emitters [18][19][20][21][22][23].Unlike in a standard Kerr medium, our squeezing does not result from a simple nonlinear polarization of the medium but from a cavity-enhanced atomic coherence which exists for weak coherent driving. Consider a twostate atom with ground and excited states |g and |e . In the absence of a resonator, the amount of squeezing is governed by the atomic coherence, σ = |g e|, and the excited-state occupation probability. The latter pro- * Publication reference: Nature 474, 623-626 (2011), www.nature.com/doifinder/10.1038/nature10170 † Present address: MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands duces incoherent scattering which destroys the squeezing. Therefore, the laser intensity must remain low to preserve the atomic and hence the optical coherence, see Supplementary Information. Under this condition, the optical squeezing is determined by the fluctuations of the atomic coherence, ∆σ 2 = ( σ − σ ) 2 , itself given by ∆σ 2 = − σ 2 owing to the fermionic character of a twostate atom, σ 2 = 0. Note that this sets an upper bound to the amount of squeezing which can be obtained, even when all the light scattered by the atom in all directions is observed.The presence of the cavity introduces two important ingredients as sketched in Fig. 1. First, the cavity mirrors spatially direct the squeezed light towards the detectors thus eliminating the need to observe the full 4π solid angle. Second, the strong coupling to the optical cavity mode makes ...

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Section: Figmentioning

confidence: 99%

Observation of squeezed light from one atom excited with two photons

Ourjoumtsev

Kubanek

Koch

et al. 2011

Nature

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“…1, has several possible applications, including preparation of superpositions of coherent states [67], continuous two-qubit parity measurements in a cavity quantum electrodynamics network [68], and low energy switches [69]. Concerning the experimental realization, basic ingredients of the scheme such as trapping of a single atom in a strongly coupled cavity and preparing of the initial atomic state have been demonstrated experimentally in [70], where the decrease in cavity field intensity for an atom in the state |↑ compared to the case of an atom in the state |↓ is used to subsequently measure the state of the atom. State preparation and readout for a single atom in a cavity have also been demonstrated in [71].…”

Section: Overview and Main Resultsmentioning

confidence: 99%

Quantum state engineering, purification, and number-resolved photon detection with high-finesse optical cavities

et al. 2010

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We propose and analyze a multi-functional setup consisting of high finesse optical cavities, beam splitters, and phase shifters. The basic scheme projects arbitrary photonic two-mode input states onto the subspace spanned by the product of Fock states |n |n with n = 0, 1, 2, . . .. This protocol does not only provide the possibility to conditionally generate highly entangled photon number states as resource for quantum information protocols but also allows one to test and hence purify this type of quantum states in a communication scenario, which is of great practical importance. The scheme is especially attractive as a generalization to many modes allows for distribution and purification of entanglement in networks. In an alternative working mode, the setup allows of quantum non demolition number resolved photodetection in the optical domain.

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“…The fermions are subject to a background lattice potential whose parameters can be controlled independently. This can be achieved, for example, by using a two-mode cavity [41]. While the atoms are coupled to one of the modes (pumped by A in Fig.…”

Section: Modelmentioning

confidence: 99%

Topological superradiant state in Fermi gases with cavity induced spin–orbit coupling

Pan

Liu

et al. 2017

Front. Phys.

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Coherently driven atomic gases inside optical cavities hold great promise for generating rich dynamics and exotic states of matter. It was shown recently that an exotic topological superradiant state exists in a two-component degenerate Fermi gas coupled to a cavity, where local order parameters coexist with global topological invariants. In this work, we characterize in detail various properties of this exotic state, focusing on the feedback interactions between the atoms and the cavity field. In particular, we demonstrate that cavity-induced interband coupling plays a crucial role in inducing the topological phase transition between the conventional and topological superradiant states. We analyze the interesting signatures in the cavity field left by the closing and reopening of the atomic bulk gap across the topological phase boundary and discuss the robustness of the topological superradiant state by investigating the steady-state phase diagram under various conditions. Furthermore, we consider the interaction effect and discuss the interplay between the pairing order in atomic ensembles and the superradiance of the cavity mode. Our work provides many valuable insights into the unique cavity-atom hybrid system under study and is helpful for future experimental exploration of the topological superradiant state.

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Cavity-Based Single Atom Preparation and High-Fidelity Hyperfine State Readout

Cited by 125 publications

References 21 publications

Observation of squeezed light from one atom excited with two photons

Observation of squeezed light from one atom excited with two photons

Quantum state engineering, purification, and number-resolved photon detection with high-finesse optical cavities

Topological superradiant state in Fermi gases with cavity induced spin–orbit coupling

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