Collective transverse cavity cooling of a dense molecular beam

Salzburger, Thomas; Ritsch, Helmut

doi:10.1088/1367-2630/11/5/055025

Cited by 27 publications

(51 citation statements)

References 38 publications

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“…In a semiclassical point particle description the time evolution of the mode amplitudes a n of the intra cavity field E(x) := n a n f n (x) is governed by the equations [14] a n (t) = (i∆ c − κ)a n (t) − iU 0…”

Section: Modelmentioning

confidence: 99%

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Atomic self-ordering in a ring cavity with counterpropagating pump fields

Ostermann

Grießer

Ritsch

2015

EPL

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The collective dynamics of mobile scatterers and light in optical resonators generates complex behaviour. For strong transverse illumination a phase transition from homogeneous to crystalline particle order appears. In contrast, a gas inside a single-side pumped ring cavity exhibits an instability towards bunching and collective acceleration called collective atomic recoil lasing (CARL). We demonstrate that by driving two orthogonally polarized counter propagating modes of a ring resonator one realises both cases within one system. The corresponding phase diagram depending on the two pump intensities exhibits regions in which either a generalized form of self-ordering towards a travelling density wave with constant centre of mass velocity or a CARL instability is formed. Controlling the cavity driving then allows to accelerate or slow down and trap a sufficiently dense beam of linearly polarizable particles.

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Section: Modelmentioning

confidence: 99%

“…This implies that if the homogeneous solution is unstable and the asymmetry exceeds the bound (14), the gas will necessarily enter the CARL regime. Eqn.…”

Section: Bgk-wavesmentioning

confidence: 99%

Atomic self-ordering in a ring cavity with counterpropagating pump fields

Ostermann

Grießer

Ritsch

2015

EPL

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“…Moreover, optical bistability [31,32], a roton-type softening in the atomic dispersion relation [26,[33][34][35] and optomechanical Bloch oscillations [36] were uncovered. Similar effects occur also for polarizable and thermal particles in a cavity at finite temperature [37][38][39].In this work, motivated by recent experiments [2, 10], we study a hybrid atom-optomechanical setup in the form of a "membrane-in-the-middle" cavity [1,2,[8][9][10][11]], see Fig. 1.…”

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confidence: 93%

Nonequilibrium Quantum Phase Transition in a Hybrid Atom-Optomechanical System

et al. 2018

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We consider a hybrid quantum many-body system formed by a vibrational mode of a nanomembrane, which interacts optomechanically with light in a cavity, and an ultracold atom gas in the optical lattice of the out-coupled light. The adiabatic elimination of the light field yields an effective Hamiltonian which reveals a competition between the force localizing the atoms and the membrane displacement. At a critical atom-membrane interaction, we find a nonequilibrium quantum phase transition from a localized symmetric state of the atom cloud to a shifted symmetry-broken state, the energy of the lowest collective excitation vanishes, and a strong atom-membrane entanglement arises. The effect occurs when the atoms and the membrane are non-resonantly coupled.Hybrid quantum systems combine complementary fields of physics, such as solid-state physics, quantum optics and atom physics, in one set-up. Recently, a hybrid atom-optomechanical system [1] has been realized experimentally [2] in which a single mechanical mode of a nanomembrane in an optical cavity is optically coupled to a far distant cloud of cold 87 Rb atoms residing in the optical potential of the out-coupled standing wave of the cavity light. When displaced, the membrane experiences the radiation pressure force of the cavity light, and in the bad-cavity limit, the field follows the membrane displacement adiabatically. This modulates the light phase which leads to a shaking of the atom gas in the lattice. The nanomechanical motion of the membrane then couples non-resonantly to the collective motion of the atoms. The aim is twofold [1][2][3][4][5][6][7]: The gas can cool the nanomembrane, and, emergent phenomena of the correlated quantum many-body system are of interest [8][9][10][11][12][13][14][15][16][17].State-of-the-art optomechanics [3-6] is nowadays able to realize optical feedback cooling [18,19] of the mechanical oscillator to its quantum-mechanical ground state [20,21]. Yet, the resolved sideband limit allows ground-state cooling only if the oscillator frequency exceeds the photon loss rate in the cavity [22][23][24]. Hence, cooling a macroscopic low-frequency nanomembrane close to its ground state is so far not possible. One promising alternative [1,7] is to utilize an ultracold atom gas, which has been demonstrated recently [2] by sympathetic cooling down to 650 mK. Current investigations aim to a coherent state transfer of robust quantum entanglement [15].Apart from cooling the nanomembrane, an interesting fundamental feature is the collective quantum-many body behavior of the hybrid system. For instance, the atom-atom interaction can in principle be coherently modulated by the back-action of the cavity light on the nanooscillator. By this, a long-range interaction emerges which resembles that of a dipolar Bose-Einstein condensate (BEC) [25]. In fact, a simpler hybrid quantum many-body system has also been implemented in the form of a BEC in an optical lattice inside a transversely pumped optical cavity. A Dicke quantum phase transition between a n...

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“…Considerable theoretical progress understanding the strongly coupled atom-field dynamics, including particle motion, has been made in past decades [3][4][5][6], and has been accompanied by impressive experimental achievements [7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…Although cooling persists, in principle, it slows down too much to be useful. One way out of this dilemma is the use of collective enhancement using a high density of particles inside the mode volume [6]. Again, in principle, the mechanism has been shown to work for precooled atoms [13], but it turns out to be technically challenging to implement the required high-pressure and low-temperature beam sources for molecules [5].…”

Section: Introductionmentioning

confidence: 99%

Optomechanical approach to cooling of small polarizable particles in a strongly pumped ring cavity

2010

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Cavity cooling of an atom works best on a cyclic optical transition in the strong coupling regime near resonance, where small-cavity photon numbers suffice for trapping and cooling. A straightforward application to the cooling of the translational motion of other polarizable particles without sharply defined two-level transitions (such as molecules) fails as optical pumping transfers the particle into uncoupled states. An alternative operation in the far-off-resonant regime generates only very slow cooling due to the reduced field-particle coupling. We suggest one can overcome this by using a strongly driven ring cavity operated in the sideband cooling regime. The dynamics can be mapped onto the optomechanics setup with a movable mirror and allows one to take advantage of a collectively enhanced field-particle coupling by large photon numbers. A linearized analytical treatment confirmed by full numerical quantum simulations predicts fast cooling despite the off-resonant small single-particle-single-photon coupling. Even ground-state translational cooling (in the external potential) can be obtained by tuning the cavity field close to the Anti-stokes sideband for sufficiently high trapping frequency. Numerical simulations show quantum jumps of the particle between the lowest two trapping levels, which can be directly and continuously monitored via scattered light intensity detection.

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Collective transverse cavity cooling of a dense molecular beam

Cited by 27 publications

References 38 publications

Atomic self-ordering in a ring cavity with counterpropagating pump fields

Atomic self-ordering in a ring cavity with counterpropagating pump fields

Nonequilibrium Quantum Phase Transition in a Hybrid Atom-Optomechanical System

Optomechanical approach to cooling of small polarizable particles in a strongly pumped ring cavity

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