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1.
W. Hiltner H. A. Freye R. J. Fosbinder J. W. Schoonover M. Kilpatrick E. F. Chase L. C. Riesch A. Janke F. Sekera G. F. Davidson J. O. Burton H. Matheson S. F. Acree G. Haugaard F. L. Vodret F. Hovorka W. C. Dearing T. Mikawa E. Newbery A. Itano S. Arakawa T. R. Ball W. B. Schmidt K. S. Bergstresser E. Vellinger A. E. Lorch F. Lux W. von Brehmer M. Déribéré A. F. Peters und A. Osol 《Fresenius' Journal of Analytical Chemistry》1935,103(7-8):285-292
Ohne Zusammenfassung 相似文献
2.
L. Lorini N. Ashby A. Brusch S. Diddams R. Drullinger E. Eason T. Fortier P. Hastings T. Heavner D. Hume W. Itano S. Jefferts N. Newbury T. Parker T. Rosenband J. Stalnaker W. Swann D. Wineland J. Bergquist 《The European physical journal. Special topics》2008,163(1):19-35
The record of atomic clock frequency comparisons at NIST over the past half-decade provides one of the tightest constraints
of any present-day temporal variations of the fundamental constants. Notably, the 6-year record of increasingly precise measurements
of the absolute frequency of the Hg+ single-ion optical clock (using the cesium primary frequency standard NIST-F1) constrains the temporal variation of the fine
structure constant α to less than 2 · 10−6yr−1 and offers a Local Position Invariance test in the framework of General Relativity. The most recent measurement of the frequency
ratio of the Al+ and Hg+ optical clocks is reported with a fractional frequency uncertainty of ±5.2 · 10−17. The record of such measurements over the last year sensitively tests for a temporal variation of α and constrains , consistent with zero. 相似文献
3.
Ben-Kish A DeMarco B Meyer V Rowe M Britton J Itano WM Jelenković BM Langer C Leibfried D Rosenband T Wineland DJ 《Physical review letters》2003,90(3):037902
Using a single, harmonically trapped 9Be(+) ion, we experimentally demonstrate a technique for generation of arbitrary states of a two-level particle confined by a harmonic potential. Rather than engineering a single Hamiltonian that evolves the system to a desired final state, we implement a technique that applies a sequence of simple operations to synthesize the state. 相似文献
4.
Bize S Diddams SA Tanaka U Tanner CE Oskay WH Drullinger RE Parker TE Heavner TP Jefferts SR Hollberg L Itano WM Bergquist JC 《Physical review letters》2003,90(15):150802
Over a two-year duration, we have compared the frequency of the 199Hg+ 5d(10)6s (2)S(1/2)(F=0)<-->5d(9)6s(2) (2)D(5/2)(F=2) electric-quadrupole transition at 282 nm with the frequency of the ground-state hyperfine splitting in neutral 133Cs. These measurements show that any fractional time variation of the ratio nu(Cs)/nu(Hg) between the two frequencies is smaller than +/-7 x 10(-15) yr(-1) (1sigma uncertainty). According to recent atomic structure calculations, this sets an upper limit to a possible fractional time variation of g(Cs)(m(e)/m(p))alpha(6.0) at the same level. 相似文献
5.
Shoji Asano Keiji Itano Kohfuku Kohda Yuriko Yamagata 《Journal of heterocyclic chemistry》1996,33(4):1115-1121
Reaction of 9-substituted (methyl or benzyl) 1-aminoadenines 1 with hydrazine afforded 9-substituted 6-hydrazinopurines 2 and 1-substituted 5-ammo-4-(4-amino-1,2,4-triazol-3-yl)imidazole ( 4 ). The product ratio of 2 to 4 rose with increasing amounts of methanol used as the solvent. When the same reaction was carried out using 1,9-dimethyladenine instead of 1 , compounds 2 and 4 were also obtained with N6,9-dimethyladenine. A possible mechanism for formation of 2 and 4 is discussed. 相似文献
6.
Leibfried D DeMarco B Meyer V Rowe M Ben-Kish A Britton J Itano WM Jelenković B Langer C Rosenband T Wineland DJ 《Physical review letters》2002,89(24):247901
We show how an experimentally realized set of operations on a single trapped ion is sufficient to simulate a wide class of Hamiltonians of a spin-1/2 particle in an external potential. This system is also able to simulate other physical dynamics. As a demonstration, we simulate the action of two nth order nonlinear optical beam splitters comprising an interferometer sensitive to phase shift in one of the interferometer beam paths. The sensitivity in determining these phase shifts increases linearly with n, and the simulation demonstrates that the use of nonlinear beam splitters (n=2,3) enhances this sensitivity compared to the standard quantum limit imposed by a linear beam splitter (n=1). 相似文献
7.
T.?SchaetzEmail author D.?Leibfried J.?Chiaverini M.D.?Barrett J.?Britton B.?DeMarco W.M.?Itano J.D.?Jost C.?Langer D.J.?Wineland 《Applied physics. B, Lasers and optics》2004,79(8):979-986
We describe the concept and experimental demonstration of the basic building blocks of a scalable quantum computer using trapped-ion qubits. The trap structure is divided into subregions where ion qubits can either be held as memory or subjected to individual rotations and multi-qubit gates in processor zones. Thus, ion qubits can become entangled in one trapping zone, then separated and distributed to separate zones (by switching control-electrode potentials) where subsequent single- and two-ion gates, and/or detection is performed. Recent work using these building blocks includes (1) demonstration of a dense-coding protocol, (2) demonstration of enhanced qubit-detection efficiency using quantum logic, (3) generation of GHZ states and their application to enhanced precision in spectroscopy, and (4) the realization of teleportation with atomic qubits. In the final section an analog quantum computer that could provide a shortcut towards quantum simulations under requirements less demanding than those for a universal quantum computer is also described. PACS 03.67.Lx; 32.80.Qk 相似文献
8.
Demonstration of a fundamental quantum logic gate 总被引:1,自引:0,他引:1
9.
The microscopic and macroscopic versions of fluid mechanics differ qualitatively. Microscopic particles obey time-reversible ordinary differential equations. The resulting particle trajectories {q(t)} may be time-averaged or ensemble-averaged so as to generate field quantities corresponding to macroscopic variables. On the other hand, the macroscopic continuum fields described by fluid mechanics follow irreversible partial differential equations. Smooth particle methods bridge the gap separating these two views of fluids by solving the macroscopic field equations with particle dynamics that resemble molecular dynamics. Recently, nonlinear dynamics have provided some useful tools for understanding the relationship between the microscopic and macroscopic points of view. Chaos and fractals play key roles in this new understanding. Non-equilibrium phase-space averages look very different from their equilibrium counterparts. Away from equilibrium the smooth phase-space distributions are replaced by fractional-dimensional singular distributions that exhibit time irreversibility. 相似文献
10.
Warren WM. McGovern 《代数通讯》2013,41(4):1636-1646
The content of a polynomial f over a commutative ring R is the ideal c(f) of R generated by the coefficients of f. A commutative ring R is said to be Gaussian if c(fg) = c(f)c(g) for every polynomials f and g in R[X]. A number of authors have formulated necessary and sufficient conditions for R(X) (respectively, R?X?) to be semihereditary, have weak global dimension at most one, be arithmetical, or be Prüfer. An open question raised by Glaz is to formulate necessary and sufficient conditions that R(X) (respectively, R?X?) have the Gaussian property. We give a necessary and sufficient condition for the rings R(X) and R?X? in terms of the ring R in case the square of the nilradical of R is zero. 相似文献