Atoms

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5254 KiB

Open AccessArticle

Novel Ion Trap Design for Strong Ion-Cavity Coupling

by Alejandro Márquez Seco, Hiroki Takahashi and Matthias Keller

Atoms 2016, 4(2), 15; https://doi.org/10.3390/atoms4020015 - 26 Apr 2016

Cited by 2 | Viewed by 6037

We present a novel ion trap design which facilitates the integration of an optical fiber cavity into the trap structure. The optical fibers are confined inside hollow electrodes in such a way that tight shielding and free movement of the fibers are simultaneously [...] Read more.

We present a novel ion trap design which facilitates the integration of an optical fiber cavity into the trap structure. The optical fibers are confined inside hollow electrodes in such a way that tight shielding and free movement of the fibers are simultaneously achievable. The latter enables in situ optimization of the overlap between the trapped ions and the cavity field. Through numerical simulations, we systematically analyze the effects of the electrode geometry on the trapping characteristics such as trap depths, secular frequencies and the optical access angle. Additionally, we simulate the effects of the presence of the fibers and confirm the robustness of the trapping potential. Based on these simulations and other technical considerations, we devise a practical trap configuration that isviable to achieve strong coupling of a single ion. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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701 KiB

Open AccessArticle

An Optomechanical Elevator: Transport of a Bloch Oscillating Bose–Einstein Condensate up and down an Optical Lattice by Cavity Sideband Amplification and Cooling

by B. Prasanna Venkatesh, Duncan H.J. O’Dell and Jonathan Goldwin

Atoms 2016, 4(1), 2; https://doi.org/10.3390/atoms4010002 - 25 Dec 2015

Cited by 4 | Viewed by 6241

Abstract

In this paper we give a new description, in terms of optomechanics, of previous work on the problem of an atomic Bose–Einstein condensate interacting with the optical lattice inside a laser-pumped optical cavity and subject to a bias force, such as gravity. An [...] Read more.

In this paper we give a new description, in terms of optomechanics, of previous work on the problem of an atomic Bose–Einstein condensate interacting with the optical lattice inside a laser-pumped optical cavity and subject to a bias force, such as gravity. An atomic wave packet in a tilted lattice undergoes Bloch oscillations; in a high-finesse optical cavity the backaction of the atoms on the light leads to a time-dependent modulation of the intracavity lattice depth at the Bloch frequency which can in turn transport the atoms up or down the lattice. In the optomechanical picture, the transport dynamics can be interpreted as a manifestation of dynamical backaction-induced sideband damping/amplification of the Bloch oscillator. Depending on the sign of the pump-cavity detuning, atoms are transported either with or against the bias force accompanied by an up- or down-conversion of the frequency of the pump laser light. We also evaluate the prospects for using the optomechanical Bloch oscillator to make continuous measurements of forces by reading out the Bloch frequency. In this context, we establish the significant result that the optical spring effect is absent and the Bloch frequency is not modified by the backaction. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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2585 KiB

Open AccessArticle

Cavity Optomechanics with Ultra Cold Atoms in Synthetic Abelian and Non-Abelian Gauge Field

by Bikash Padhi and Sankalpa Ghosh

Atoms 2016, 4(1), 1; https://doi.org/10.3390/atoms4010001 - 25 Dec 2015

Cited by 1 | Viewed by 7702

Abstract

In this article we present a pedagogical discussion of some of the optomechanical properties of a high finesse cavity loaded with ultracold atoms in laser induced synthetic gauge fields of different types. Essentially, the subject matter of this article is an amalgam of [...] Read more.

In this article we present a pedagogical discussion of some of the optomechanical properties of a high finesse cavity loaded with ultracold atoms in laser induced synthetic gauge fields of different types. Essentially, the subject matter of this article is an amalgam of two sub-fields of atomic molecular and optical (AMO) physics namely, the cavity optomechanics with ultracold atoms and ultracold atoms in synthetic gauge field. After providing a brief introduction to either of these fields we shall show how and what properties of these trapped ultracold atoms can be studied by looking at the cavity (optomechanical or transmission) spectrum. In presence of abelian synthetic gauge field we discuss the cold-atom analogue of Shubnikov de Haas oscillation and its detection through cavity spectrum. Then, in the presence of a non-abelian synthetic gauge field (spin-orbit coupling), we see when the electromagnetic field inside the cavity is quantized, it provides a quantum optical lattice for the atoms, leading to the formation of different quantum magnetic phases. We also discuss how these phases can be explored by studying the cavity transmission spectrum. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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497 KiB

Open AccessArticle

Two-Photon Collective Atomic Recoil Lasing

by James A. McKelvie and Gordon R.M. Robb

Atoms 2015, 3(4), 495-508; https://doi.org/10.3390/atoms3040495 - 20 Nov 2015

Viewed by 4272

Abstract

We present a theoretical study of the interaction between light and a cold gasof three-level, ladder conﬁguration atoms close to two-photon resonance. In particular, weinvestigate the existence of collective atomic recoil lasing (CARL) instabilities in differentregimes of internal atomic excitation and compare to [...] Read more.

We present a theoretical study of the interaction between light and a cold gasof three-level, ladder conﬁguration atoms close to two-photon resonance. In particular, weinvestigate the existence of collective atomic recoil lasing (CARL) instabilities in differentregimes of internal atomic excitation and compare to previous studies of the CARL instabilityinvolving two-level atoms. In the case of two-level atoms, the CARL instability is quenchedat high pump rates with signiﬁcant atomic excitation by saturation of the (one-photon)coherence, which produces the optical forces responsible for the instability and rapid heatingdue to high spontaneous emission rates. We show that in the two-photon CARL schemestudied here involving three-level atoms, CARL instabilities can survive at high pump rateswhen the atoms have signiﬁcant excitation, due to the contributions to the optical forces frommultiple coherences and the reduction of spontaneous emission due to transitions betweenthe populated states being dipole forbidden. This two-photon CARL scheme may form thebasis of methods to increase the effective nonlinear optical response of cold atomic gases. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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1060 KiB

Open AccessArticle

Cavity Quantum Electrodynamics of Continuously Monitored Bose-Condensed Atoms

by Mark D. Lee and Janne Ruostekoski

Atoms 2015, 3(3), 450-473; https://doi.org/10.3390/atoms3030450 - 23 Sep 2015

Cited by 3 | Viewed by 5072

Abstract

We study cavity quantum electrodynamics of Bose-condensed atoms that are subjected to continuous monitoring of the light leaking out of the cavity. Due to a given detection record of each stochastic realization, individual runs spontaneously break the symmetry of the spatial profile of [...] Read more.

We study cavity quantum electrodynamics of Bose-condensed atoms that are subjected to continuous monitoring of the light leaking out of the cavity. Due to a given detection record of each stochastic realization, individual runs spontaneously break the symmetry of the spatial profile of the atom cloud and this symmetry can be restored by considering ensemble averages over many realizations. We show that the cavity optomechanical excitations of the condensate can be engineered to target specific collective modes. This is achieved by exploiting the spatial structure and symmetries of the collective modes and light fields. The cavity fields can be utilized both for strong driving of the collective modes and for their measurement. In the weak excitation limit the condensate–cavity system may be employed as a sensitive phonon detector which operates by counting photons outside the cavity that have been selectively scattered by desired phonons. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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1022 KiB

Open AccessArticle

A Realization of a Quasi-Random Walk for Atoms in Time-Dependent Optical Potentials

by Torsten Hinkel, Helmut Ritsch and Claudiu Genes

Atoms 2015, 3(3), 433-449; https://doi.org/10.3390/atoms3030433 - 23 Sep 2015

Cited by 3 | Viewed by 5391

Abstract

We consider the time dependent dynamics of an atom in a two-color pumped cavity, longitudinally through a side mirror and transversally via direct driving of the atomic dipole. The beating of the two driving frequencies leads to a time dependent effective optical potential [...] Read more.

We consider the time dependent dynamics of an atom in a two-color pumped cavity, longitudinally through a side mirror and transversally via direct driving of the atomic dipole. The beating of the two driving frequencies leads to a time dependent effective optical potential that forces the atom into a non-trivial motion, strongly resembling a discrete random walk behavior between lattice sites. We provide both numerical and analytical analysis of such a quasi-random walk behavior. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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1111 KiB

Open AccessArticle

Probing and Manipulating Fermionic and Bosonic Quantum Gases with Quantum Light

by Thomas J. Elliott, Gabriel Mazzucchi, Wojciech Kozlowski, Santiago F. Caballero-Benitez and Igor B. Mekhov

Atoms 2015, 3(3), 392-406; https://doi.org/10.3390/atoms3030392 - 2 Sep 2015

Cited by 17 | Viewed by 5627

Abstract

We study the atom-light interaction in the fully quantum regime, with the focus on off-resonant light scattering into a cavity from ultracold atoms trapped in an optical lattice. The detection of photons allows the quantum nondemolition (QND) measurement of quantum correlations of the [...] Read more.

We study the atom-light interaction in the fully quantum regime, with the focus on off-resonant light scattering into a cavity from ultracold atoms trapped in an optical lattice. The detection of photons allows the quantum nondemolition (QND) measurement of quantum correlations of the atomic ensemble, distinguishing between different quantum states. We analyse the entanglement between light and matter and show how it can be exploited for realising multimode macroscopic quantum superpositions, such as Schrödinger cat states, for both bosons and fermions. We provide examples utilising different measurement schemes and study their robustness to decoherence. Finally, we address the regime where the optical lattice potential is a quantum dynamical variable and is modified by the atomic state, leading to novel quantum phases and significantly altering the phase diagram of the atomic system. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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1926 KiB

Open AccessArticle

Cavity-Assisted Generation of Sustainable Macroscopic Entanglement of Ultracold Gases

by Chaitanya Joshi and Jonas Larson

Atoms 2015, 3(3), 348-366; https://doi.org/10.3390/atoms3030348 - 4 Aug 2015

Cited by 7 | Viewed by 4454

Abstract

Prospects for reaching persistent entanglement between two spatially-separated atomic Bose–Einstein condensates are outlined. The system setup comprises two condensates loaded in an optical lattice, which, in return, is confined within a high-Q optical resonator. The system is driven by an external laser that [...] Read more.

Prospects for reaching persistent entanglement between two spatially-separated atomic Bose–Einstein condensates are outlined. The system setup comprises two condensates loaded in an optical lattice, which, in return, is confined within a high-Q optical resonator. The system is driven by an external laser that illuminates the atoms, such that photons can scatter into the cavity. In the superradiant phase, a cavity field is established, and we show that the emerging cavity-mediated interactions between the two condensates is capable of entangling them despite photon losses. This macroscopic atomic entanglement is sustained throughout the time-evolution apart from occasions of sudden deaths/births. Using an auxiliary photon mode and coupling it to a collective quadrature of the two condensates, we demonstrate that the auxiliary mode’s squeezing is proportional to the atomic entanglement, and as such, it can serve as a probe field of the macroscopic entanglement. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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321 KiB

Open AccessArticle

Influence of Virtual Photon Process on the Generation of Squeezed Light from Atoms in an Optical Cavity

by Aranya B. Bhattacherjee

Atoms 2015, 3(3), 339-347; https://doi.org/10.3390/atoms3030339 - 24 Jul 2015

Cited by 3 | Viewed by 4162

Abstract

We show that a collection of two-level atoms in an optical cavity beyond the rotating wave approximation and in the dispersive-adiabatic and non-dispersive adiabatic regime constitutes a nonlinear medium and is capable of generating squeezed state of light. It is found that squeezing [...] Read more.

We show that a collection of two-level atoms in an optical cavity beyond the rotating wave approximation and in the dispersive-adiabatic and non-dispersive adiabatic regime constitutes a nonlinear medium and is capable of generating squeezed state of light. It is found that squeezing produced in the non-dispersive adiabatic regime is significantly high compared to that produced in the dispersive-adiabatic limit. On the other hand, we also show that it could be possible to observe the Dicke superradiant quantum phase transition in the dispersive-adiabatic regime where the Ã2 term is negligible. Such a system can be an essential component of a larger quantum-communication system. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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3270 KiB

Open AccessArticle

Photon-Induced Spin-Orbit Coupling in Ultracold Atoms inside Optical Cavity

by Lin Dong, Chuanzhou Zhu and Han Pu

Atoms 2015, 3(2), 182-194; https://doi.org/10.3390/atoms3020182 - 26 May 2015

Cited by 22 | Viewed by 6358

Abstract

We consider an atom inside a ring cavity, where a plane-wave cavity field together with an external coherent laser beam induces a two-photon Raman transition between two hyperfine ground states of the atom. This cavity-assisted Raman transition induces effective coupling between atom’s internal [...] Read more.

We consider an atom inside a ring cavity, where a plane-wave cavity field together with an external coherent laser beam induces a two-photon Raman transition between two hyperfine ground states of the atom. This cavity-assisted Raman transition induces effective coupling between atom’s internal degrees of freedom and its center-of-mass motion. In the meantime, atomic dynamics exerts a back-action to cavity photons. We investigate the properties of this system by adopting a mean-field and a full quantum approach, and show that the interplay between the atomic dynamics and the cavity field gives rise to intriguing nonlinear phenomena. Full article

(This article belongs to the Special Issue Cavity Quantum Electrodynamics with Ultracold Atoms)

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