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91.
Matsukevich DN Chanelière T Bhattacharya M Lan SY Jenkins SD Kennedy TA Kuzmich A 《Physical review letters》2005,95(4):040405
We describe a new experimental approach to probabilistic atom-photon (signal) entanglement. Two qubit states are encoded as orthogonal collective spin excitations of an unpolarized atomic ensemble. After a programmable delay, the atomic excitation is converted into a photon (idler). Polarization states of both the signal and the idler are recorded and are found to be in violation of the Bell inequality. Atomic coherence times exceeding several microseconds are achieved by switching off all the trapping fields--including the quadrupole magnetic field of the magneto-optical trap--and zeroing out the residual ambient magnetic field. 相似文献
92.
Absolute distance measurements can be performed with an interferometric method that uses only a single tunable laser. This method has one major drawback, because a small target movement of the order of one wavelength during a measurement will be interpreted as a movement of one synthetic wavelength. This effect is usually mitigated by adding a second (nonscanning) laser. We show that absolute distance measurements can be performed with only one laser if the movements encountered are smooth, on the time scale of one measurement. In this case the movement errors can be compensated with a simple algorithm that combines several subsequent measurements. First experimental results show good agreement with theory. 相似文献
93.
Bacteriorhodopsin (bR) is a reversible photochromic protein that can be used as a holographic medium. The dichroic absorption of the bR molecule is polarization dependent, thereby allowing for the recording of polarization holograms. The properties of polarization holograms can be used to multiplex two independent images in a single bR film. A new technique and associated polarization-multiplexing scheme are demonstrated that allow for simultaneous readout of two orthogonally polarized images while achieving a high normalized diffraction efficiency for each of the individual images. 相似文献
94.
95.
S.?Dey S.S.?Dasgupta C.C.?Dey P.?Bhattacharya 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):193-197
A kinematically complete experiment has been performed to study the α-n final-state interaction (FSI) in the α + d ↦α + p
+ n break-up reaction at 50 MeV incident energy for the alpha-particles. For this, we have chosen four pairs of correlation
angles for the outgoing alpha and protons. These are ( θα = 18°, θp = 42°), ( θα = 20°, θp = 45°), ( θα = 22°, θp = 42°) and ( θα = 22°, θp = 47°), selected kinematically where the allowed phase spaces are in favor of the α-n final-state interaction. Our experimental
data show strong α-n FSI in all the selected configurations. Also, the FSI is found to be stronger at the lower alpha-particle
energy when two FSI peaks appear in the same configuration.
Received: 17 June 2002 / Accepted: 3 October 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: dey_s2001@yahoo.com; Present address: 445 Waupelani Drive, Apt. F3, State College, PA 16801, USA.
Communicated by M. Gar?on 相似文献
96.
Letd>1, and letα andβ be mixing ? d -actions by automorphisms of zero-dimensional compact abelian groupsX andY, respectively. By analyzing the homoclinic groups of certain sub-actions ofα andβ we prove that, if the restriction ofα to some subgroup Γ ? ? d of infinite index is expansive and has completely positive entropy, then every measurable factor mapφ: (X, α)→(Y, β) is almost everywhere equal to an affine map. The hypotheses of this result are automatically satisfied if the actionα contains an expansive automorphismα n ,n ∈ ? d , or ifα arises from a nonzero prime ideal in the ring of Laurent polynomials ind variables with coefficients in a finite prime field. Both these corollaries generalize the main theorem in [9]. In several examples we show that this kind of isomorphism rigidity breaks down if our hypotheses are weakened. 相似文献
97.
Time-resolved differential transmission measurements of self-assembled In0.4Ga0.6As quantum dots clearly indicate a phonon bottleneck between the n = 2 and n = 1 electronic levels. The key to this observation is the generation of electrons in dots where there are no holes so that electron-hole scattering does not mask the bottleneck. We use a simple carrier capture model consisting of two capture configurations to explain the bottleneck signal and offer arguments to rule out other possible sources of the signal. 相似文献
98.
We formulate the conditions under which the dynamics of a continuously measured quantum system becomes indistinguishable from that of the corresponding classical system. In particular, we demonstrate that even in a classically chaotic system the quantum state vector conditioned by the measurement remains localized and, under these conditions, follows a trajectory characterized by the classical Lyapunov exponent. 相似文献
99.
Bhattacharya M Goodman CD Raghavan RS Palarczyk M Garcia A Rapaport J van Heerden IJ Zupranski P 《Physical review letters》2000,85(21):4446-4449
We report a 0 degrees 176Yb(p,n)176Lu measurement at IUCF where we used 120 and 160 MeV protons and the energy dependence method to determine Gamow-Teller (GT) matrix elements relative to the model independent Fermi matrix element. The data show that there is an isolated concentration of GT strength in the low-lying 1(+) states making the proposed Low Energy Neutrino Spectroscopy detector (based on neutrino captures on 176Yb) sensitive to pp and 7Be neutrinos and a promising detector to resolve the solar neutrino problem. 相似文献
100.
Rajneesh Mohan Kiran Singh Shovit Bhattacharya N.K. Gaur S.K. Gupta 《Solid State Communications》2007,141(11):605-609
Both oxygen and calcium play important roles in inducing superconductivity in Y Ba2Cu3Oy (YBCO), which is an antiferromagnetic insulator at low O and Ca content. O induces superconductivity in Ca-free YBCO, while Ca does similarly in oxygen-deficient YBCO. For doping oxygen HgO was used as it decomposes at 476 °C into Hg, which escapes from the matrix leaving the crystal unaltered, and O, which provide a way to dope O in YBCO. Considering these facts, polycrystalline samples of Y 1−xCaxBa2Cu3Oy with x=0, 0.1 and 0.2 with and without HgO addition were prepared through a solid-state reaction method. The samples were sintered at 950 °C in open atmosphere. These synthesized samples were characterized through using the X-ray diffraction technique (XRD) for phase evaluation, scanning electron microscopy (SEM) for grain morphology, energy dispersive X-ray analysis (EDX) for compositional analysis and the four-contact measurement technique for determining the superconducting transition temperature. 相似文献