Observation of the persistent-current splitting of a third-sound resonator

Ellis, F. M.; Luo, Haishan

doi:10.1103/physrevb.39.2703

Cited by 26 publications

(61 citation statements)

References 12 publications

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“…To give an experimentally relevant example, in the following we study the interaction of a quantized vortex with sound modes in a disk-shaped resonator with a free ('Neumann') boundary condition (see appendix D.1). This analysis is applicable to geometries used in superfluid helium experiments [30,44,45] with a microtoroidal optomechanical resonator of R∼30 μm radius (see figure 3(a)), those of [31,56,60,61], and also experiments with two-dimensional Bose-Einstein-condensates, which are confined by a hard-walled trap [53].…”

Section: Resultsmentioning

confidence: 99%

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Modelling of vorticity, sound and their interaction in two-dimensional superfluids

et al. 2019

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Vorticity in two-dimensional superfluids is subject to intense research efforts due to its role in quantum turbulence, dissipation and the BKT phase transition. Interaction of sound and vortices is of broad importance in Bose-Einstein condensates and superfluid helium. However, both the modelling of the vortex flow field and of its interaction with sound are complicated hydrodynamic problems, with analytic solutions only available in special cases. In this work, we develop methods to compute both the vortex and sound flow fields in an arbitrary two-dimensional domain. Further, we analyse the dispersive interaction of vortices with sound modes in a two-dimensional superfluid and develop a model that quantifies this interaction for any vortex distribution on any two-dimensional bounded domain, possibly non-simply connected, exploiting analogies with fluid dynamics of an ideal gas and electrostatics. As an example application we use this technique to propose an experiment that should be able to unambiguously detect single circulation quanta in a helium thin film.

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Section: Resultsmentioning

confidence: 99%

“…In order for the vortex-induced frequency splitting Δf (equation (11)) experienced by a third-sound wave [31,60] to reveal quantized steps, several challenges must be addressed.…”

Section: Requirements For Detection Of Single Vortices/circulation Qumentioning

confidence: 99%

Modelling of vorticity, sound and their interaction in two-dimensional superfluids

et al. 2019

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“…The increased mode confinement arising from the micron scale geometry achieved here compared to previous third sound experiments (50,70), combined with atomically smooth surfaces and greatly enhanced measurement precision, provides the prospect to explore dissipation mechanisms in new regimes where surface roughness is negligible, phonon-phonon and phonon-vortex interactions are enhanced via confinement, and driving far out of equilibrium is not required.…”

mentioning

confidence: 82%

“…In superfluid helium-4, the elementary excitations are phonons and rotons; with techniques such as neutron and light scattering used to probe their behaviour since the 1960s (26,159). However, quite generally, such techniques have been limited to measurements of average properties of bulk superfluid (159); or to observations of the driven response far out of thermal equilibrium (43,50,70). Consequently, the microscopic behaviour of strongly interacting condensates, like superfluid helium-4, is not fully understood.…”

Section: Superfluid Helium-4mentioning

confidence: 99%

“…Superfluid films form naturally on surfaces due to the combination of ultra-low viscosity and attractive van der Waals forces. Excitations in such films, known as third sound (50,70,122,152), manifest as perturbations to their thickness with the restoring force provided by the van der Waals interaction. The physical structure of the resonator provides a template for the self-assembling film, acting to confine third sound modes at microscale in two dimensions, while their radial dimension is determined by the film thickness.…”

Section: Superfluid Optomechanics With Thin Filmsmentioning

confidence: 99%

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Cavity optomechanics with feedback and fluids

Harris¹

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Mechanical oscillators are extensively used in applications ranging from chronometry using quartz oscillators to ultra fast sensors and actuators as in atomic force microscopy and spin/mass/force sensing. The continuous push towards miniaturized high precision sensors has motivated the development of increasingly high quality mechanical oscillators at length scales as small as nanometers, with integration into cryogenic environments used to avoid thermal noise. This raises the prospect of observing mechanical oscillators in a new regime where their dynamics are dictated by quantum, rather than classical, mechanics. Utilizing the quantum behaviour of mechanical oscillators promises to enhance applications in sensing and metrology. In this thesis experimental techniques are reported that enhance optomechanical sensors and enable fundamental experiments in quantum optomechanics. In particular, there is a strong emphasis towards experimentally developing detection based feedback control techniques, for example to enable feedback cooling towards the mechanical ground state or to stabilize parasitic instabilities. In addition to these experimental advances, I detail a real-time estimation strategy that invalidates the use of linear feedback to enhanced the performance of linear optomechanical sensors. Finally, a unique and promising optomechanical systems is developed and characterized based on surface waves of a thin film of superfluid helium-4.The first topic considered in this thesis is feedback cooling of a generalized optomechanical system. In that chapter a detailed mathematical treatment is derived that highlights the importance of using a dual probe position measurement to accurately characterize a feedback cooled oscillator. The theoretical results are then experimentally verified using a microtoroidal resonator controlled via electrostatic actuation. This chapter provides a brief introduction into feedback cooling and serves to introduce the fundamental optomechanical system that underscores the majority of the work presented in this thesis. In the following chapter, the problem of estimating an unknown force driving a linear oscillator is considered. In this context it is well known that linear feedback control can improve the performance of nonlinear mechanical sensors. However, for completely linear systems, feedback is often cited as a mechanism to enhance bandwidth, sensitivity or resolution. For such systems it is shown that as long as the oscillator dynamics are known, there exists a real-time estimation strategy that reproduces the same measurement record as any arbitrary feedback protocol. Consequently, some form of nonlinearity is required in the controller, plant, or sensor, to gain any advantage beyond estimation alone. This result holds true in both quantum and classical systems, with non-stationary forces and feedback, and in the general case of non-Gaussian and correlated noise. As a proof-of-principle, a specific case of feedback enhanced incoherent force resolution is experimentally ...

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Non-Minimal Higgs Bosons: Theory and Phenomenology

Haber

1990

Higgs Particle(s)

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Observation of the persistent-current splitting of a third-sound resonator

Cited by 26 publications

References 12 publications

Modelling of vorticity, sound and their interaction in two-dimensional superfluids

Modelling of vorticity, sound and their interaction in two-dimensional superfluids

Cavity optomechanics with feedback and fluids

Non-Minimal Higgs Bosons: Theory and Phenomenology

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