Dicke‐type phase transition in a multimode optomechanical system

Mumford, J.; O’Dell, D. H. J.; Larson, Jonas

doi:10.1002/andp.201400105

Cited by 14 publications

(15 citation statements)

References 67 publications

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“…Our system also provides a platform for studying nonlinear optomechanics and chaotic dynamics, such as dynamical multistability 30 . Furthermore, at low temperatures and with a high mechanical quality factor, a quantum phase transition may be observable in systems of this nature 31 . Specifically, an optomechanical system can be made sufficiently cold—with a nominal dephasing rate slower than its resonance frequency—and sideband resolved to be laser cooled to its ground state before buckling 32 .…”

Section: Discussionmentioning

confidence: 99%

Observation of optomechanical buckling transitions

Kemiktarak

Fan

et al. 2017

Nat Commun

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Correlated phases of matter provide long-term stability for systems as diverse as solids, magnets and potential exotic quantum materials. Mechanical systems, such as buckling transition spring switches, can have engineered, stable configurations whose dependence on a control variable is reminiscent of non-equilibrium phase transitions. In hybrid optomechanical systems, light and matter are strongly coupled, allowing engineering of rapid changes in the force landscape, storing and processing information, and ultimately probing and controlling behaviour at the quantum level. Here we report the observation of first- and second-order buckling transitions between stable mechanical states in an optomechanical system, in which full control of the nature of the transition is obtained by means of the laser power and detuning. The underlying multiwell confining potential we create is highly tunable, with a sub-nanometre distance between potential wells. Our results enable new applications in photonics and information technology, and may enable explorations of quantum phase transitions and macroscopic quantum tunnelling in mechanical systems.

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Section: Discussionmentioning

confidence: 99%

Observation of optomechanical buckling transitions

Kemiktarak

Fan

et al. 2017

Nat Commun

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“…One way of achieving collective couplings as in Eqns. (1), (2), and (3) would be their effective engineering in a quantum simulator [18,[40][41][42]. However, collective couplings also naturally arise when the distance between the two-level systems is much smaller than the wavelength of the reservoir modes with which they interact.…”

Section: Implementationsmentioning

confidence: 99%

“…For a collective coupling, however, the relaxation time scales as 1/N and the maximum radiation intensity scales as N 2 [16]. A setup in which the collective coupling approximation is well justified can be obtained by confining the two-level atoms in a region much smaller than the wavelength of the electromagnetic field, but such collective couplings may also be engineered for instance using trapped ions [17] or opto-mechanical setups [18].…”

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confidence: 99%

Collective couplings: Rectification and supertransmittance

2016

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We investigate heat transport between two thermal reservoirs that are coupled via a large spin composed of N identical two level systems. One coupling implements the dissipative Dicke superradiance. The other coupling is locally of the pure-dephasing type and requires to go beyond the standard weak-coupling limit by employing a Bogoliubov mapping in the corresponding reservoir. After the mapping, the large spin is coupled to a collective mode with the original pure-dephasing interaction, but the collective mode is dissipatively coupled to the residual oscillators. Treating the large spin and the collective mode as the system, a standard master equation approach is now able to capture the energy transfer between the two reservoirs. Assuming fast relaxation of the collective mode, we derive a coarse-grained rate equation for the large spin only and discuss how the original Dicke superradiance is affected by the presence of the additional reservoir. Our main finding is a cooperatively enhanced rectification effect due to the interplay of supertransmittant heat currents (scaling quadratically with N ) and the asymmetric coupling to both reservoirs. For large N , the system can thus significantly amplify current asymmetries under bias reversal, functioning as a heat diode. We also briefly discuss the case when the couplings of the collective spin are locally dissipative, showing that the heat-diode effect is still present. I. MOTIVATIONThe study of radiative effects in two-level systems has a long history. Here, the spin-boson model [1] takes a very prominent role. Originating from the interaction of a two-level atom with the electromagnetic field [2], it is often used as a toy model in many other contexts. Not surprisingly, it has become a canonical model to explore fundamental methods of open systems [3][4][5] and effectively arises in a rather large number of physical systems and effects, including e.g. the dynamics of light-harvesting complexes [6], detectors [7], and the interaction of quantum dots with generalized environments [8].Ideally, one aims at a reduced description taking only the finite-dimensional spin dynamics into account. However, when the number of spins is increased, the curse of dimensionality -the exponential growth of the system Hilbert space with its size -usually inhibits investigations of large spin-boson models. When additional symmetries come into play -e.g. when the spins have the same splitting and couple collectively to all other componentssimplified descriptions are applicable. Collective effects may for example dramatically influence the dephasing behavior of the environment, leading to phenomena such as super-and sub-decoherence [9,10]. Furthermore, they play a significant role in the modelling of light-harvesting complexes [11][12][13][14]. Perhaps one of the clearest manifesta- * gernot.schaller@tu-berlin.de tions of collective behaviour is Dicke superradiance [15]. Here, the collectivity of the coupling between N two-level atoms and a low-temperature bosonic reservoir induces an...

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“…Note that for ∆ = 0 only the supercritical pitchfork bifurcation occurs. In this situation symmetry breaking is formally related to the superradiant phase transition in the Dicke model [21]. x 0…”

Section: Symmetry Breakingmentioning

confidence: 99%

“…1), with a focus on the self-sustained oscillations that break the reflection symmetry of the specific setup considered here. Our work is motivated by previous studies of similar setups that addressed, e.g., the symmetry breaking at zero detuning [21], the onset of chaotic motion [22], or pattern formation and buckling phase transitions for a flexible membrane [23,24]. We extend these studies along three lines.…”

Section: Introductionmentioning

confidence: 97%

Symmetry-breaking oscillations in membrane optomechanics

2016

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We study the classical dynamics of a membrane inside a cavity in the situation where this optomechanical system possesses a reflection symmetry. Symmetry breaking occurs through supercritical and subcritical pitchfork bifurcations of the static fixed point solutions. Both bifurcations can be observed through variation of the laser-cavity detuning, which gives rise to a boomerang-like fixed point pattern with hysteresis. The symmetry-breaking fixed points evolve into self-sustained oscillations when the laser intensity is increased. In addition to the analysis of the accompanying Hopf bifurcations we describe these oscillations at finite amplitudes with an ansatz that fully accounts for the frequency shift relative to the natural membrane frequency. We complete our study by following the route to chaos for the membrane dynamics.

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Dicke‐type phase transition in a multimode optomechanical system

Cited by 14 publications

References 67 publications

Observation of optomechanical buckling transitions

Observation of optomechanical buckling transitions

Collective couplings: Rectification and supertransmittance

Symmetry-breaking oscillations in membrane optomechanics

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