Quantum backaction in spinor-condensate magnetometry

Steinke, Steven; Singh, Swati; Meystre, Pierre; Schwab, Keith; Vengalattore, Mukund

doi:10.1103/physreva.88.063809

Cited by 6 publications

(6 citation statements)

References 20 publications

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“…The entries of the Fisher matrix can be calculated using (38)(39)(40), relations (9)(10)(11), and the property of the polylogarithm z ∂Liα(z) ∂z…”

Section: A Homogeneous Ideal Gasesmentioning

confidence: 99%

Precision measurements of temperature and chemical potential of quantum gases

Marzolino¹,

Braun²

2013

Phys. Rev. A

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We investigate the sensitivity with which the temperature and the chemical potential characterizing quantum gases can be measured. We calculate the corresponding quantum Fisher information matrices for both fermionic and bosonic gases. For the latter, particular attention is devoted to the situation close to the Bose-Einstein condensation transition, which we examine not only for the standard scenario in three dimensions, but also for generalized condensation in lower dimensions, where the bosons condense in a subspace of Hilbert space instead of a unique ground state, as well as condensation at fixed volume or fixed pressure. We show that Bose Einstein condensation can lead to sub-shot noise sensitivity for the measurement of the chemical potential. We also examine the influence of interactions on the sensitivity in three different models, and show that mean-field and contact interactions deteriorate the sensitivity but only slightly for experimentally accessible weak interactions.

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“…The entries of the Fisher matrix can be calculated using (38)(39)(40), relations (9)(10)(11), and the property of the polylogarithm z ∂Liα(z) ∂z…”

Section: A Homogeneous Ideal Gasesmentioning

confidence: 99%

Precision measurements of temperature and chemical potential of quantum gases

Marzolino¹,

Braun²

2013

Phys. Rev. A

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“…To achieve this, one cannot measure the displacement of the resonator [13], but instead must measure the energy directly -preferably without destroying the quantum state, a so-called quantum non-demolition (QND) measurement. Whereas the accuracy in continuously measuring two conjugate quantities is limited by the Heisenberg uncertainty principle to the standard quantum limit (SQL) [13], QND measurements allow for continuous measurements of an observable to be taken to arbitrary precision [14][15][16][17]. Here our interest lies in a QND measurement of the energy, and thereby the number of phonons [18].…”

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confidence: 99%

Nonlinear optomechanics in the stationary regime

et al. 2014

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We have observed nonlinear transduction of the thermomechanical motion of a nanomechanical resonator when detected as laser transmission through a sideband unresolved optomechanical cavity. Nonlinear detection mechanisms are of considerable interest as special cases allow for quantum nondemolition measurements of the mechanical resonator's energy. We investigate the origin of the nonlinearity in the optomechanical detection apparatus and derive a theoretical framework for the nonlinear signal transduction, and the optical spring effect, from both nonlinearities in the optical transfer function and second order optomechanical coupling. By measuring the dependence of the linear and nonlinear signal transduction -as well as the mechanical frequency shift -on laser detuning from optical resonance, we provide estimates of the contributions from the linear and quadratic optomechanical couplings.Cavity optomechanics has resulted in new levels of extremely precise displacement transduction [1, 2] of ultrahigh frequency resonators [3]. This has created much interest in pursuing quantum measurements [4] of nanomechancial devices [5][6][7], as well as dynamical back action cooling [8][9][10][11].One of the most fundamental, and as of yet unattained, quantum measurements that could be performed is that of the quantized energy eigenstates of a nanomechanical resonator (as has been demonstrated with an electron in a cyclotron orbit [12]). To achieve this, one cannot measure the displacement of the resonator [13], but instead must measure the energy directly -preferably without destroying the quantum state, a so-called quantum non-demolition (QND) measurement. Whereas the accuracy in continuously measuring two conjugate quantities is limited by the Heisenberg uncertainty principle to the standard quantum limit (SQL) [13], QND measurements allow for continuous measurements of an observable to be taken to arbitrary precision [14][15][16][17]. Here our interest lies in a QND measurement of the energy, and thereby the number of phonons [18]. In an optomechanical system, this is expected to be possible by having strong second order optomechanical coupling [19][20][21][22]. This has been demonstrated in membrane-in-the-middle Fabry-Pérot cavities [23,24], however it has been pointed out there remains first order coupling between the two optical modes, possibly obscuring QND measurements [25].Signal from second order optomechanical coupling, hence measurement of x 2 , will display mechanical peaks at twice the fundamental frequency. However, we would also expect that nonlinear transduction of the displacement, x, of a mechanical resonator from a nonlinear optical transfer function would also appear at harmonics of the mechanical resonance frequency, as has been observed [26][27][28].In this Letter we report observation of peaks in the mechanical power spectra at exactly twice the fundamental mechanical frequency, as shown in Fig. 1. We derive a model for the origin of the harmonic signal, as well as the optical spring effect, from bo...

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“…[228][229][230] For an atomic magnetometer based upon a spinor BEC with a off-resonant optical field, Steinke et al analyzes how its sensitivity depends on the dispersive interaction between the spinor BEC and the off-resonant optical field. 231 More recently, the detection of a weak alternate-current magnetic field has been demonstrated by applying spin-echo techniques to a spin-2 atomic BEC. 232…”

Section: Summary and Discussionmentioning

confidence: 99%

Quantum Metrology With Cold Atoms

Huang

Zhong

et al. 2014

Annual Review of Cold Atoms and Molecules

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Quantum metrology is the science that aims to achieve precision measurements by making use of quantum principles. Attribute to the well-developed techniques of manipulating and detecting cold atoms, cold atomic systems provide an excellent platform for implementing precision quantum metrology. In this chapter, we review the general procedures of quantum metrology and some experimental progresses in quantum metrology with cold atoms. Firstly, we give the general framework of quantum metrology and the calculation of quantum Fisher information, which is the core of quantum parameter estimation. Then, we introduce the quantum interferometry with single and multiparticle states. In particular, for some typical multiparticle states, we analyze their ultimate precision limits and show how quantum entanglement could enhance the measurement precision beyond the standard quantum limit. Further, we review some experimental progresses in quantum metrology with cold atomic systems.

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Quantum backaction in spinor-condensate magnetometry

Cited by 6 publications

References 20 publications

Precision measurements of temperature and chemical potential of quantum gases

Precision measurements of temperature and chemical potential of quantum gases

Nonlinear optomechanics in the stationary regime

Quantum Metrology With Cold Atoms

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