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Gajdacz M, Hilliard AJ, Kristensen MA, Pedersen PL, Klempt C, Arlt JJ, Sherson JF. Preparation of Ultracold Atom Clouds at the Shot Noise Level. PHYSICAL REVIEW LETTERS 2016; 117:073604. [PMID: 27563964 DOI: 10.1103/physrevlett.117.073604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Indexed: 06/06/2023]
Abstract
We prepare number stabilized ultracold atom clouds through the real-time analysis of nondestructive images and the application of feedback. In our experiments, the atom number N∼10^{6} is determined by high precision Faraday imaging with uncertainty ΔN below the shot noise level, i.e., ΔN<sqrt[N]. Based on this measurement, feedback is applied to reduce the atom number to a user-defined target, whereupon a second imaging series probes the number stabilized cloud. By this method, we show that the atom number in ultracold clouds can be prepared below the shot noise level.
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Affiliation(s)
- M Gajdacz
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - A J Hilliard
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - M A Kristensen
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - P L Pedersen
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - C Klempt
- Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, D-30167 Hannover, Germany
| | - J J Arlt
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - J F Sherson
- Institut for Fysik og Astronomi, Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus C, Denmark
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Ott H. Single atom detection in ultracold quantum gases: a review of current progress. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:054401. [PMID: 27093632 DOI: 10.1088/0034-4885/79/5/054401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The recent advances in single atom detection and manipulation in experiments with ultracold quantum gases are reviewed. The discussion starts with the basic principles of trapping, cooling and detecting single ions and atoms. The realization of single atom detection in ultracold quantum gases is presented in detail and the employed methods, which are based on light scattering, electron scattering, field ionization and direct neutral particle detection are discussed. The microscopic coherent manipulation of single atoms in a quantum gas is also covered. Various examples are given in order to highlight the power of these approaches to study many-body quantum systems.
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Affiliation(s)
- Herwig Ott
- Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67663 Kaiserslautern, Germany
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Béguin JB, Bookjans EM, Christensen SL, Sørensen HL, Müller JH, Polzik ES, Appel J. Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice. PHYSICAL REVIEW LETTERS 2014; 113:263603. [PMID: 25615331 DOI: 10.1103/physrevlett.113.263603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Indexed: 06/04/2023]
Abstract
We demonstrate preparation and detection of an atom number distribution in a one-dimensional atomic lattice with the variance -14 dB below the Poissonian noise level. A mesoscopic ensemble containing a few thousand atoms is trapped in the evanescent field of a nanofiber. The atom number is measured through dual-color homodyne interferometry with a pW-power shot noise limited probe. Strong coupling of the evanescent probe guided by the nanofiber allows for a real-time measurement with a precision of ±8 atoms on an ensemble of some 10(3) atoms in a one-dimensional trap. The method is very well suited for generating collective atomic entangled or spin-squeezed states via a quantum nondemolition measurement as well as for tomography of exotic atomic states in a one-dimensional lattice.
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Affiliation(s)
- J-B Béguin
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - E M Bookjans
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - S L Christensen
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - H L Sørensen
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - J H Müller
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - E S Polzik
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
| | - J Appel
- QUANTOP, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100 Copenhagen, Denmark
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Blumkin A, Rinott S, Schley R, Berkovitz A, Shammass I, Steinhauer J. Observing atom bunching by the Fourier slice theorem. PHYSICAL REVIEW LETTERS 2013; 110:265301. [PMID: 23848890 DOI: 10.1103/physrevlett.110.265301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 05/24/2013] [Indexed: 06/02/2023]
Abstract
By a novel reciprocal space analysis of the measurement, we report a calibrated in situ observation of the bunching effect in a 3D ultracold gas. The calibrated measurement with no free parameters confirms the role of the exchange symmetry and the Hanbury Brown-Twiss effect in the bunching. Also, the enhanced fluctuations of the bunching effect give a quantitative measure of the increased isothermal compressibility. We use 2D images to probe the 3D gas, using the same principle by which computerized tomography reconstructs a 3D image of a body. The powerful reciprocal space technique presented is applicable to systems with one, two, or three dimensions.
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Affiliation(s)
- A Blumkin
- Department of Physics, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
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Shammass I, Rinott S, Berkovitz A, Schley R, Steinhauer J. Phonon dispersion relation of an atomic Bose-Einstein condensate. PHYSICAL REVIEW LETTERS 2012; 109:195301. [PMID: 23215394 DOI: 10.1103/physrevlett.109.195301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Indexed: 06/01/2023]
Abstract
We measure the time oscillations of a freely evolving standing wave of phonons in a Bose-Einstein condensate. We present the technique of short Bragg pulses, which stimulates the standing wave. The subsequent oscillations are observed in situ. The frequency of the oscillations gives the dispersion relation, the amplitude gives the static structure factor, and the decay gives the dephasing time. The new technique gives orders of magnitude more sensitivity than Bragg spectroscopy, allowing for the observation of deviations from the local density approximation. Specifically, it is seen that the phonons undergo a transition from three dimensions to one dimension, when their wavelength becomes longer than the transverse radius of the condensate. The one-dimensional regime contains an inflection point in the dispersion relation, a decrease in the superfluid critical velocity, a minimum in the group velocity, and an increase in the lifetime of the standing wave oscillations.
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Affiliation(s)
- I Shammass
- Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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Bookjans EM, Hamley CD, Chapman MS. Strong quantum spin correlations observed in atomic spin mixing. PHYSICAL REVIEW LETTERS 2011; 107:210406. [PMID: 22181864 DOI: 10.1103/physrevlett.107.210406] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Indexed: 05/31/2023]
Abstract
We have observed sub-Poissonian spin correlations generated by collisionally induced spin mixing in a spin-1 Bose-Einstein condensate. We measure a quantum noise reduction of -7 dB (-10 dB corrected for detection noise) below the standard quantum limit for the corresponding coherent spin states. The spin fluctuations are detected as atom number differences in the spin states using fluorescent imaging that achieves a detection noise floor of 8 atoms per spin component for a probe time of 100 μs.
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Affiliation(s)
- Eva M Bookjans
- School of Physics, Georgia Institute of Technology, Atlanta, 30332-0430, USA
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Jacqmin T, Armijo J, Berrada T, Kheruntsyan KV, Bouchoule I. Sub-Poissonian fluctuations in a 1D Bose gas: from the quantum quasicondensate to the strongly interacting regime. PHYSICAL REVIEW LETTERS 2011; 106:230405. [PMID: 21770488 DOI: 10.1103/physrevlett.106.230405] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Indexed: 05/31/2023]
Abstract
We report on local, in situ measurements of atom number fluctuations in slices of a one-dimensional Bose gas on an atom chip setup. By using current modulation techniques to prevent cloud fragmentation, we are able to probe the crossover from weak to strong interactions. For weak interactions, fluctuations go continuously from super- to sub-Poissonian as the density is increased, which is a signature of the transition between the subregimes where the two-body correlation function is dominated, respectively, by thermal and quantum contributions. At stronger interactions, the super-Poissonian region disappears, and the fluctuations go directly from Poissonian to sub-Poissonian, as expected for a "fermionized" gas.
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Affiliation(s)
- Thibaut Jacqmin
- Laboratoire Charles Fabry, Institut d'Optique, UMR8501 du CNRS, Palaiseau, France
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Jaskula JC, Bonneau M, Partridge GB, Krachmalnicoff V, Deuar P, Kheruntsyan KV, Aspect A, Boiron D, Westbrook CI. Sub-poissonian number differences in four-wave mixing of matter waves. PHYSICAL REVIEW LETTERS 2010; 105:190402. [PMID: 21231151 DOI: 10.1103/physrevlett.105.190402] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Indexed: 05/30/2023]
Abstract
We demonstrate sub-Poissonian number differences in four-wave mixing of Bose-Einstein condensates of metastable helium. The collision between two Bose-Einstein condensates produces a scattering halo populated by pairs of atoms of opposing velocities, which we divide into several symmetric zones. We show that the atom number difference for opposing zones has sub-Poissonian noise fluctuations, whereas that of nonopposing zones is well described by shot noise. The atom pairs produced in a dual number state are well adapted to sub-shot-noise interferometry and studies of Einstein-Podolsky-Rosen-type nonlocality tests.
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Affiliation(s)
- J-C Jaskula
- Laboratoire Charles Fabry de l'Institut d'Optique, CNRS, Univ Paris-Sud, Campus Polytechnique RD128 91127 Palaiseau, France
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Sanner C, Su EJ, Keshet A, Gommers R, Shin YI, Huang W, Ketterle W. Suppression of density fluctuations in a quantum degenerate Fermi gas. PHYSICAL REVIEW LETTERS 2010; 105:040402. [PMID: 20867822 DOI: 10.1103/physrevlett.105.040402] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Indexed: 05/29/2023]
Abstract
We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10 000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems.
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Affiliation(s)
- Christian Sanner
- MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, and Department of Physics, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, USA
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Whitlock S, Ockeloen CF, Spreeuw RJC. Sub-Poissonian atom-number fluctuations by three-body loss in mesoscopic ensembles. PHYSICAL REVIEW LETTERS 2010; 104:120402. [PMID: 20366518 DOI: 10.1103/physrevlett.104.120402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Indexed: 05/29/2023]
Abstract
We show that three-body loss of trapped atoms leads to sub-Poissonian atom-number fluctuations. We prepare hundreds of dense ultracold ensembles in an array of magnetic microtraps which undergo rapid three-body decay. The shot-to-shot fluctuations of the number of atoms per trap are sub-Poissonian, for ensembles comprising 50-300 atoms. The measured relative variance or Fano factor F=0.53+/-0.22 agrees very well with the prediction by an analytic theory (F=3/5) and numerical calculations. These results will facilitate studies of quantum information science with mesoscopic ensembles.
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Affiliation(s)
- S Whitlock
- Van der Waals-Zeeman Institute, University of Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam, The Netherlands.
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