26
|
Meyer V, Rowe MA, Kielpinski D, Sackett CA, Itano WM, Monroe C, Wineland DJ. Experimental demonstration of entanglement-enhanced rotation angle estimation using trapped ions. PHYSICAL REVIEW LETTERS 2001; 86:5870-5873. [PMID: 11415382 DOI: 10.1103/physrevlett.86.5870] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2001] [Indexed: 05/23/2023]
Abstract
We experimentally investigate three methods, utilizing different atomic observables and entangled states, to increase the sensitivity of rotation angle measurements beyond the "standard quantum limit" for nonentangled states. All methods use a form of quantum mechanical "squeezing." In a system of two entangled trapped (9)Be(+) ions we observe a reduction in uncertainty of rotation angle below the standard quantum limit for all three methods including all sources of noise. As an application, we demonstrate an increase in precision of frequency measurement in a Ramsey spectroscopy experiment.
Collapse
|
27
|
Udem T, Diddams SA, Vogel KR, Oates CW, Curtis EA, Lee WD, Itano WM, Drullinger RE, Bergquist JC, Hollberg L. Absolute frequency measurements of the Hg+ and Ca optical clock transitions with a femtosecond laser. PHYSICAL REVIEW LETTERS 2001; 86:4996-4999. [PMID: 11384404 DOI: 10.1103/physrevlett.86.4996] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2001] [Indexed: 05/23/2023]
Abstract
The frequency comb created by a femtosecond mode-locked laser and a microstructured fiber is used to phase coherently measure the frequencies of both the Hg+ and Ca optical standards with respect to the SI second. We find the transition frequencies to be f(Hg) = 1 064 721 609 899 143(10) Hz and f(Ca) = 455 986 240 494 158(26) Hz, respectively. In addition to the unprecedented precision demonstrated here, this work is the precursor to all-optical atomic clocks based on the Hg+ and Ca standards. Furthermore, when combined with previous measurements, we find no time variations of these atomic frequencies within the uncertainties of the absolute value of( partial differential f(Ca)/ partial differential t)/f(Ca) < or =8 x 10(-14) yr(-1) and the absolute value of(partial differential f(Hg)/ partial differential t)/f(Hg) < or =30 x 10(-14) yr(-1).
Collapse
|
28
|
Rowe MA, Kielpinski D, Meyer V, Sackett CA, Itano WM, Monroe C, Wineland DJ. Experimental violation of a Bell's inequality with efficient detection. Nature 2001; 409:791-4. [PMID: 11236986 DOI: 10.1038/35057215] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Local realism is the idea that objects have definite properties whether or not they are measured, and that measurements of these properties are not affected by events taking place sufficiently far away. Einstein, Podolsky and Rosen used these reasonable assumptions to conclude that quantum mechanics is incomplete. Starting in 1965, Bell and others constructed mathematical inequalities whereby experimental tests could distinguish between quantum mechanics and local realistic theories. Many experiments have since been done that are consistent with quantum mechanics and inconsistent with local realism. But these conclusions remain the subject of considerable interest and debate, and experiments are still being refined to overcome 'loopholes' that might allow a local realistic interpretation. Here we have measured correlations in the classical properties of massive entangled particles (9Be+ ions): these correlations violate a form of Bell's inequality. Our measured value of the appropriate Bell's 'signal' is 2.25 +/- 0.03, whereas a value of 2 is the maximum allowed by local realistic theories of nature. In contrast to previous measurements with massive particles, this violation of Bell's inequality was obtained by use of a complete set of measurements. Moreover, the high detection efficiency of our apparatus eliminates the so-called 'detection' loophole.
Collapse
|
29
|
Kielpinski D, Meyer V, Rowe MA, Sackett CA, Itano WM, Monroe C, Wineland DJ. A decoherence-free quantum memory using trapped ions. Science 2001; 291:1013-5. [PMID: 11232562 DOI: 10.1126/science.1057357] [Citation(s) in RCA: 382] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We demonstrate a decoherence-free quantum memory of one qubit. By encoding the qubit into the decoherence-free subspace (DFS) of a pair of trapped 9Be+ ions, we protect the qubit from environment-induced dephasing that limits the storage time of a qubit composed of a single ion. We measured the storage time under ambient conditions and under interaction with an engineered noisy environment and observed that encoding into the DFS increases the storage time by up to an order of magnitude. The encoding reversibly transfers an arbitrary qubit stored in a single ion to the DFS of two ions.
Collapse
|
30
|
Vogel KR, Diddams SA, Oates CW, Curtis EA, Rafac RJ, Itano WM, Bergquist JC, Fox RW, Lee WD, Wells JS, Hollberg L. Direct comparison of two cold-atom-based optical frequency standards by using a femtosecond-laser comb. OPTICS LETTERS 2001; 26:102-104. [PMID: 18033520 DOI: 10.1364/ol.26.000102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
With a fiber-broadened, femtosecond-laser frequency comb, the 76-THz interval between two laser-cooled optical frequency standards was measured with a statistical uncertainty of 2x10(-13) in 5 s , to our knowledge the best short-term instability thus far reported for an optical frequency measurement. One standard is based on the calcium intercombination line at 657 nm, and the other, on the mercury ion electric-quadrupole transition at 282 nm. By linking this measurement to the known Ca frequency, we report a new frequency value for the Hg(+) clock transition with an improvement in accuracy of ~10(5) compared with its best previous measurement.
Collapse
|
31
|
Sullivan DB, Bergquist JC, Bollinger JJ, Drullinger RE, Itano WM, Jefferts SR, Lee WD, Meekhof D, Parker TE, Walls FL, Wineland DJ. Primary Atomic Frequency Standards at NIST. JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 2001; 106:47-63. [PMID: 27500017 PMCID: PMC4865291 DOI: 10.6028/jres.106.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The development of atomic frequency standards at NIST is discussed and three of the key frequency-standard technologies of the current era are described. For each of these technologies, the most recent NIST implementation of the particular type of standard is described in greater detail. The best relative standard uncertainty achieved to date for a NIST frequency standard is 1.5×10(-15). The uncertainties of the most recent NIST standards are displayed relative to the uncertainties of atomic frequency standards of several other countries.
Collapse
|
32
|
Rafac RJ, Young BC, Beall JA, Itano WM, Wineland DJ, Bergquist JC. Sub-dekahertz ultraviolet spectroscopy of 199Hg+. PHYSICAL REVIEW LETTERS 2000; 85:2462-2465. [PMID: 10978082 DOI: 10.1103/physrevlett.85.2462] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2000] [Indexed: 05/23/2023]
Abstract
Using a laser that is frequency locked to a Fabry-Perot etalon of high finesse and stability, we probe the 5d(10)6s (2)S(1/2)(F = 0)<-->5d(9)6s(2) (2)D(5/2)(F = 2) Deltam(F) = 0 electric-quadrupole transition of a single laser-cooled 199Hg+ ion stored in a cryogenic radio-frequency ion trap. We observe Fourier-transform limited linewidths as narrow as 6.7 Hz at 282 nm ( 1.06x10(15) Hz), yielding a line Q approximately 1.6x10(14). We perform a preliminary measurement of the 5d(9)6s(2) (2)D(5/2) electric-quadrupole shift due to interaction with the static fields of the trap, and discuss the implications for future trapped-ion optical frequency standards.
Collapse
|
33
|
Mitchell TB, Bollinger JJ, Dubin DHE, Huang X, Itano WM, Baughman RH. Direct observations of structural phase transitions in planar crystallized ion plasmas. Science 1998; 282:1290-3. [PMID: 9812887 DOI: 10.1126/science.282.5392.1290] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Laser-cooled 9Be+ ions confined in two-dimensionally extended lattice planes were directly observed, and the images were used to characterize the structural phases of the ions. Five different stable crystalline phases were observed, and the energetically favored structure could be sensitively tuned by changing the areal density of the confined ions. The experimental results are in good agreement with theoretical predictions for the planar (infinite in two dimensions) one-component plasma. Qualitatively similar structural phase transitions occur, or are predicted to occur, in other experimentally realizable planar systems.
Collapse
|
34
|
Wineland DJ, Monroe C, Itano WM, Leibfried D, King BE, Meekhof DM. Experimental Issues in Coherent Quantum-State Manipulation of Trapped Atomic Ions. JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 1998; 103:259-328. [PMID: 28009379 PMCID: PMC4898965 DOI: 10.6028/jres.103.019] [Citation(s) in RCA: 276] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/04/1998] [Indexed: 05/02/2023]
Abstract
Methods for, and limitations to, the generation of entangled states of trapped atomic ions are examined. As much as possible, state manipulations are described in terms of quantum logic operations since the conditional dynamics implicit in quantum logic is central to the creation of entanglement. Keeping with current interest, some experimental issues in the proposal for trappedion quantum computation by J. I. Cirac and P. Zoller (University of Innsbruck) are discussed. Several possible decoherence mechanisms are examined and what may be the more important of these are identified. Some potential applications for entangled states of trapped-ions which lie outside the immediate realm of quantum computation are also discussed.
Collapse
|
35
|
Itano WM, Bollinger JJ, Tan JN, Jelenkovic B, Huang X, Wineland DJ. Bragg diffraction from crystallized ion plasmas. Science 1998; 279:686-9. [PMID: 9445470 DOI: 10.1126/science.279.5351.686] [Citation(s) in RCA: 156] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Single crystals of a one-component plasma were observed by optical Bragg diffraction. The plasmas contained 10(5) to 10(6) single-positive beryllium-9 ions (9Be+) at particle densities of 10(8) to 10(9) per cubic centimeter. In approximately spherical plasmas, single body-centered cubic (bcc) crystals or, in some cases, two or more bcc crystals having fixed orientations with respect to each other were observed. In some oblate plasmas, a mixture of bcc and face-centered cubic ordering was seen. Knowledge of the properties of one-component plasma crystals is required for models of white dwarfs and neutron stars, which are believed to contain matter in that form.
Collapse
|
36
|
Wineland DJ, Monroe C, Meekhof DM, King BE, Leibfried D, Itano WM, Bergquist JC, Berkeland D, Bollinger JJ, Miller J. Quantum state manipulation of trapped atomic ions. Proc Math Phys Eng Sci 1998. [DOI: 10.1098/rspa.1998.0168] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
37
|
Monroe C, Meekhof DM, King BE, Leibfried D, Itano WM, Wineland DJ. Manipulating the Motion of a Single Trapped Atom. Acc Chem Res 1996. [DOI: 10.1021/ar950252i] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
38
|
Bollinger JJ, Itano WM, Wineland DJ, Heinzen DJ. Optimal frequency measurements with maximally correlated states. PHYSICAL REVIEW A 1996; 54:R4649-R4652. [PMID: 9914139 DOI: 10.1103/physreva.54.r4649] [Citation(s) in RCA: 857] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
39
|
Monroe C, Meekhof DM, Leibfried D, King BE, Itano WM, Wineland DJ. Single-Atom Quantum Logic Gate and “Schrödinger Cat” State. ACTA ACUST UNITED AC 1996. [DOI: 10.1364/opn.7.12.0013_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
40
|
Leibfried D, Meekhof DM, King BE, Monroe C, Itano WM, Wineland DJ. Experimental Determination of the Motional Quantum State of a Trapped Atom. PHYSICAL REVIEW LETTERS 1996; 77:4281-4285. [PMID: 10062500 DOI: 10.1103/physrevlett.77.4281] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
41
|
Meekhof DM, Monroe C, King BE, Itano WM, Wineland DJ. Generation of nonclassical motional states of a trapped atom. PHYSICAL REVIEW LETTERS 1996; 76:1796-1799. [PMID: 10060523 DOI: 10.1103/physrevlett.76.1796] [Citation(s) in RCA: 161] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
42
|
Monroe C, Meekhof DM, King BE, Itano WM, Wineland DJ. Demonstration of a fundamental quantum logic gate. PHYSICAL REVIEW LETTERS 1995; 75:4714-4717. [PMID: 10059979 DOI: 10.1103/physrevlett.75.4714] [Citation(s) in RCA: 220] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
43
|
Monroe C, Meekhof DM, King BE, Jefferts SR, Itano WM, Wineland DJ, Gould P. Resolved-sideband Raman cooling of a bound atom to the 3D zero-point energy. PHYSICAL REVIEW LETTERS 1995; 75:4011-4014. [PMID: 10059792 DOI: 10.1103/physrevlett.75.4011] [Citation(s) in RCA: 139] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
44
|
Itano WM, Bergquist JC, Bollinger JJ, Gilligan JM, Heinzen DJ, Moore FL, Raizen MG, Wineland DJ. Erratum: Quantum projection noise: Population fluctuations in two-level systems. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1995; 51:1717. [PMID: 9920631 DOI: 10.1103/physreva.51.1717] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|
45
|
Wineland DJ, Bollinger JJ, Itano WM, Heinzen DJ. Squeezed atomic states and projection noise in spectroscopy. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1994; 50:67-88. [PMID: 9910869 DOI: 10.1103/physreva.50.67] [Citation(s) in RCA: 167] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
46
|
Bollinger JJ, Heinzen DJ, Moore FL, Itano WM, Wineland DJ, Dubin DH. Electrostatic modes of ion-trap plasmas. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1993; 48:525-545. [PMID: 9909626 DOI: 10.1103/physreva.48.525] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
47
|
Itano WM, Bergquist JC, Bollinger JJ, Gilligan JM, Heinzen DJ, Moore FL, Raizen MG, Wineland DJ. Quantum projection noise: Population fluctuations in two-level systems. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1993; 47:3554-3570. [PMID: 9909363 DOI: 10.1103/physreva.47.3554] [Citation(s) in RCA: 131] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
48
|
Eichmann U, Bergquist JC, Bollinger JJ, Gilligan JM, Itano WM, Wineland DJ, Raizen MG. Young's interference experiment with light scattered from two atoms. PHYSICAL REVIEW LETTERS 1993; 70:2359-2362. [PMID: 10053542 DOI: 10.1103/physrevlett.70.2359] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
49
|
Wineland DJ, Bollinger JJ, Itano WM, Moore FL, Heinzen DJ. Spin squeezing and reduced quantum noise in spectroscopy. PHYSICAL REVIEW A 1992; 46:R6797-R6800. [PMID: 9908086 DOI: 10.1103/physreva.46.r6797] [Citation(s) in RCA: 740] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
50
|
Raizen MG, Gilligan JM, Bergquist JC, Itano WM, Wineland DJ. Ionic crystals in a linear Paul trap. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1992; 45:6493-6501. [PMID: 9907772 DOI: 10.1103/physreva.45.6493] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|