Thermometry of ultracold atoms by electromagnetically induced transparency

Peters, Thorsten; Wittrock, Benjamin; Blatt, F. J.; Halfmann, Thomas; Yatsenko, L. P.

doi:10.1103/physreva.85.063416

Cited by 19 publications

(18 citation statements)

References 25 publications

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“…( 5 ). This interferometric thermometry is similar to some spectroscopic ones such as recoil-induced resonance 39 , 40 or stimulated two photons transition 41 , 42 . From our measurements, we get T = 0.5(1) μK, μs and mm/s.…”

Section: Resultssupporting

confidence: 59%

Non-Abelian adiabatic geometric transformations in a cold strontium gas

et al. 2018

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Topology, geometry, and gauge fields play key roles in quantum physics as exemplified by fundamental phenomena such as the Aharonov–Bohm effect, the integer quantum Hall effect, the spin Hall, and topological insulators. The concept of topological protection has also become a salient ingredient in many schemes for quantum information processing and fault-tolerant quantum computation. The physical properties of such systems crucially depend on the symmetry group of the underlying holonomy. Here, we study a laser-cooled gas of strontium atoms coupled to laser fields through a four-level resonant tripod scheme. By cycling the relative phases of the tripod beams, we realize non-Abelian SU(2) geometrical transformations acting on the dark states of the system and demonstrate their non-Abelian character. We also reveal how the gauge field imprinted on the atoms impact their internal state dynamics. It leads to a thermometry method based on the interferometric displacement of atoms in the tripod beams.

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Section: Resultssupporting

confidence: 59%

Non-Abelian adiabatic geometric transformations in a cold strontium gas

et al. 2018

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“…2. We determine these rates via a stroboscopic measurement of the thermal broadening of narrow resonances of dark-states caused by coherent population trapping [9,19] (Fig. 2a).…”

Section: Fig 2 Temperature Dynamics Of the Engine (A)mentioning

confidence: 99%

A single-atom heat engine

Roßnagel

Dawkins

Tolazzi

et al. 2016

Science

770

645

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We report the experimental realization of a single-atom heat engine. An ion is confined in a linear Paul trap with tapered geometry and driven thermally by coupling it alternately to hot and cold reservoirs. The output power of the engine is used to drive a harmonic oscillation. From direct measurements of the ion dynamics, we determine the thermodynamic cycles for various temperature differences of the reservoirs. We use these cycles to evaluate power P and efficiency η of the engine, obtaining up to P = 342 yJ and η = 2.8 , consistent with analytical estimations. Our results demonstrate that thermal machines can be reduced to the ultimate limit of single atoms.Heat engines have played a central role in our modern society since the industrial revolution. Converting thermal energy into mechanical work, they are ubiquitously employed to generate motion, from cars to airplanes [1]. The working fluid of a macroscopic engine typically contains of the order of 10 24 particles. In the last decade, dramatic experimental progress has lead to the miniaturization of thermal machines down to the microscale, using microelectromechanical [2], piezoresistive [3] and cold atom [4] systems, as well as single colloidal particles [5,6] and single molecules [7]. In his 1959 talk "There is plenty of room at the bottom", Richard Feynman already envisioned tiny motors working at the atomic level [8]. However, to date no such device has been built.Here we report the realization of a single-atom heat engine whose working agent is an ion, held within a modified linear Paul trap. We use laser cooling and electric field noise to engineer cold and hot reservoirs. We further employ fast thermometry methods to determine the temperature of the ion [9]. The thermodynamic cycle of the engine is established for various temperature differences of the reservoirs, from which we deduce work and heat, and thus power output and efficiency. We additionally show that the work produced by the engine can be effectively stored and used to drive an oscillator against friction. Our device demonstrates the working principles of a thermodynamic heat engine with a working agent reduced to the ultimate single particle limit, thus fulfilling Feynman's dream.Trapped ions offer an exceptional degree of preparation, control and measurement of their parameters, allowing for ground state cooling [10] and coupling to engineered reservoirs [11]. Owing to their unique properties, they have recently become invaluable tools for the investigation of quantum thermodynamics [12][13][14][15][16][17]. They additionally provide an ideal setup to operate and characterize a single particle heat engine.In our experiment, a single 40 Ca + ion is trapped in a linear Paul trap with a funnel-shaped electrode geometry, as shown in Fig. 1a [15]. The electrodes are driven symmetrically at a radio-frequency voltage of 830 V pp at 21 MHz, resulting in a tapered harmonic pseudopotential [10] of the form U = (m/2) i ω 2 i i 2 , where m is the atomic mass and i ∈ {x, y} denote the trap axes as...

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“…The two other decoherence contributions come from dephasing of the stored collective excitation, which can be written in the ideal case as |ψ = (1/ √ N ) j e iφj |g...s j ...g where N is the number of atoms. The first process, also related to the temperature, is the motional dephasing due to the strong angular dependence of EIT [41,42]. The Doppler shift of the two-photon transition results in a phase change between the storage and retrieval times ∆φ j = ∆ k.( r s − r r ) where r s and r r are the initial and final positions of the jth atom, and ∆ k is the wave-vector mismatch of the control and guided signal [43].…”

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confidence: 99%

Demonstration of a Memory for Tightly Guided Light in an Optical Nanofiber

et al. 2015

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We report the experimental observation of slow-light and coherent storage in a setting where light is tightly confined in the transverse directions. By interfacing a tapered optical nanofiber with a cold atomic ensemble, electromagnetically induced transparency is observed and light pulses at the single-photon level are stored in and retrieved from the atomic medium with an overall efficiency of (10 ± 0.5)%. Collapses and revivals can be additionally controlled by an applied magnetic field. Our results based on subdiffraction-limited optical mode interacting with atoms via the strong evanescent field demonstrate an alternative to free-space focusing and a novel capability for information storage in an all-fibered quantum network.PACS numbers: 03.67.Hk, 42.50.Gy, 42.50.Ex, 42.81.Qb Over the recent years, the physical implementation of quantum interfaces between light and matter has triggered a very active research, with unique applications to quantum optics and quantum information networks [1,2]. Within this context, a promising approach consists in coupling light with atomic ensembles [3,4]. Reversible quantum memories have been realized in a variety of ensemble-based systems, e.g. doped crystals and free-space collection of alkali atoms [5]. Significant advances have been made, including the demonstration of entanglement between remote memories and the development of first rudimentary capabilities for quantum repeater architectures [6][7][8][9]. However, free-space focusing as used in these seminal works is limiting the coupling one can obtain and the connectivity to fiber networks.Interfacing guided light with atoms has therefore been foreseen as a promising alternative, enabling longer interaction length, large optical depth and potential nonlinear interactions at low power level [2]. A first possible implementation consists in encasing a vapor into the hollow core of a photonic-crystal fiber, confining thus atoms and photons in the waveguide. Slow-light, alloptical switching and few-photon modulation have been demonstrated [10][11][12]. Recently, single-photon-level Raman memory has been realized with larger core fibers, with storage limited to the 10 ns time-scale [13]. Another approach can be based on an even tighter confinement of light in a nanoscale waveguide leading to a large evanescent field that can interact with atoms located in the vicinity. This situation can be ideally realized with optical nanofibers exhibiting subwavelength diameter [14]. Using a nanofiber in a hot Rubidium vapor, nonlinear interactions and low-power saturation have been reported [15][16][17], albeit with very short transit time of hot atoms in the evanescent field and large broadening.In this new avenue of research, the unique prospects of combining cold atoms with nanofibers have triggered vast theoretical and experimental efforts. Pioneering works investigated the interaction of a small number of atoms with the guided mode, including fluorescence coupling and surface interactions [18][19][20], and the dipole trapping of...

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Thermometry of ultracold atoms by electromagnetically induced transparency

Cited by 19 publications

References 25 publications

Non-Abelian adiabatic geometric transformations in a cold strontium gas

Non-Abelian adiabatic geometric transformations in a cold strontium gas

A single-atom heat engine

Demonstration of a Memory for Tightly Guided Light in an Optical Nanofiber

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