We point of that using the state-of-the-art (or soon to be) intense ultrafast laser technology, violent acceleration of electrons that may be suitable for testing general relativistic effects can be realized in the laboratory settings. In particular we demonstrate that the Unruh radiation is detectable, in principle, beyond the conventional radiation (most notably the Larmor radiation) background noise, by taking the advantages of their specific dependences on the laser power, their different characters in spectral-angular distributions, and the time structure of the signals.
[C10.02] A Proposed Experimental Test of Unsharp Spin Variables
Millard Baublitz (Boston University)
Most physicists have conceded for many years that Bell's Theorem and the experiments by Aspect et al. indicate nonlocal correlations between pairs of particles in entangled systems. The experiments of Aspect et al. used photons, but Kar and Roy[1] recently demonstrated that the Bell inequalities for spin 1/2 particles must be modified if unsharp spin variables[2] are considered. Furthermore, the modified Bell inequalities may not be violated by quantum mechanics if the observables are sufficiently unsharp. In this talk an experiment[3] will be discussed that can place experimental limits on the unsharpness of spin variables, and if unsharp variables prove to be significant, then the experiment might indicate causes of the unsharpness.
[1] G. Kar and S. Roy, Phys. Lett. A 199, 12 (1995).
[2] P. Busch, M. Grabowski, and P. Lahti, Operational Quantum Physics, (Springer, Berlin, 1995).
[3] M. Baublitz, to be published.
[C10.03] Bell's Theorem Faces Symmetries of Experimental System.
Joshua H. Rosenbloom (1000 Chiswell Lane, Silver Spring, MD 20901)
This abstract was not submitted electronically.
[C10.04] Measurement of the phase shift due to the acceleration of matter in a neutron interferometer
K. C. Littrell, S. A. Werner (University of Missouri-Columbia Physics Department and Research Reactor, Columbia, MO 65211)
The nonlinear nature of the index of refraction of neutrons in matter causes the phase shift produced by neutrons passing through a matter prism to be influenced by the motion of the prism. In this presentation we extend discussion of the neutron Fizeau effect to include the effects of the acceleration of matter inside a neutron interferometer on the measured quantum mechanical phase. We use semiclassical techniques to evaluate the phase shift expected considering both a uniformly accelerating prism and a sinusoidally oscillating prism. We also present a fully quantum mechanical, quasienergy solution for the case of the oscillating prism and compare the results and implications of the two methods. We describe an experiment to observe these phase shifts.
[C10.05] Scalar Aharonov-Bohm Effect with Longitudinally Polarized Neutrons
W.-T. Lee, O. Motrunich, B. E. Allman, S. A. Werner (Univ. of Missouri-Columbia, Missouri 65211.)
A scalar potential in the temporal part of the action integral gives rise to the scalar Aharonov-Bohm (SAB) effect. In the first SAB experiment done using neutron interferometry(B. E. Allman, A. Cimmino, A. G. Klein, G. I. Opat, H. Kaiser, and S. A. Werner, Phys. Rev. Lett. 68, 2409 (1992).), a short square current pulse was applied to a solenoid while thermal neutrons were traveling inside along the solenoid axis, subjecting the neutron magnetic moments \mu to a spatially uniform magnetic induction B. The scalar interaction -\mu ^.B produced a quantum mechanical phase shift. However, the use of unpolarized neutrons gave rise to the interpretational objection that the phase shift came from a rotation of the classical neutron spins due to the torque -\muxB.(M. Peshkin, Phys. Rev. Lett. 69, 2017 (1992).) We have now carried out a similar SAB experiment using neutrons polarized longitudinally along the B-field. In this ar!
rangement, the torque is zero and
the spatially uniform B-field exerts no force. The phase shift as expected from the SAB theory was clearly observed.
[C10.06] The Validity/Utility of the Naive Time-reversal Operation
H. E. Conzett (Lawrence Berkeley Laboratory)
A long accepted test of time-reversal (T) symmetry in the beta-decay of polarized nuclei has been associated with the T-odd spin-operator component Sy = S.(k1 x k2), where S is the nuclear spin, k1 (k2) is the electron (neutrino) momentum and y is normal to the decay plane. The measured observable is the decay analyzing power Ay. More recently the same analyzing power has been measured in the decay of polarized Z bosons into three jets [1]. Here, however, it is claimed that the corresponding Sy is odd under Tn, "naive time reversal", which reverses momenta and spins without interchanging the initial and final states. As such, not being a true time-reversal operation, a nonzero value of the corresponding (Tn-odd) observable Ay would not signify any violation of T symmetry. This clear inconsistency with respect to T symmetry in beta and Z boson decay analyzing powers is discussed, and it is shown that the Tn operation has no validity with respect to T symmetry.
1. K Abe et al., Phys. Rev. Lett. 75, 4173 (1995).
[C10.07] Ehrenfest's Theorem and the Quantum Hall Effect
Malcolm H. Mac Gregor (Lawrence Livermore National Laboratory)
Ehrenfest's theorem as applied to an orbiting electron in a magnetic field B states that the quantum mechanical solution goes over quantitatively into the corresponding classical limit, provided that (a) the field B is constant over the orbit, and (b) the electron wave packet is small as compared to the size of the orbit. In the case of the two-dimensional electron motion in the quantum Hall effect, condition (a) is satisfied, but (b) is not. However, the correspondence between the Hall quantum mechanical Landau electron orbitals and the quantized classical orbits is close enough that the latter can be used to delimit the solutions of the former, and conversely. The solutions thus allowed by Ehrenfest's theorem are precisely those that match the observed denominators n~=~1,~3,~5,~... in the quantum Hall effect, where the Hall "filling fraction" is \nu~=~m/n, with m~=~all integers. This suggests that integer (n~=~1) and fractional (n~=~3,~5,~...) quantized Hall plateaus should have similar explanations, as is also indicated by the similarities in the experimental systematics of these two quantum phenomena.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livemore National Laboratory under contract W-7405-ENG-48
[C10.08] Heat Without Heat
Elihu Lubkin (University of Wisconsin--Milwaukee 53201--0413)
Logic of the Second Law of Thermodynamics demands acquisition of naked entropy. Accordingly, the leanest liaison between systems is not a diathermic membrane, it is a purely informational tickler, leaking no appreciable energy. The subsystem here is a thermodynamic universe, which gets `heated' entropically, yet without gaining calories. Quantum Mechanics graciously supports that(Lubkin,~E. and Lubkin,~T., International Journal of Theoretical Physics,32), 933-943 (1993) (at a cost of about 1 bit) through entanglement---across this least permeable of membranes---with what is beyond that universe. Heat without heat(Also v. forthcoming Proceedings of the 4th Drexel University Conference of September 1994) is the aspirin for Boltzmann's headache, conserving entropy in mechanical isolation, even while increasing entropy in thermodynamic isolation.
[C10.09] Observation of Atomic Antihydrogen
David Christian (Fermilab), Glenn Blanford, Keith Gollwitzer, George Zioulas, Jonas Schultz, Mark Mandelkern (U.C. Irvine), Charles Munger
The status of the Fermilab antihydrogen experiment (E862) will be presented. The experiment uses the Fermilab Antiproton Accumulator and the E835 (Charmonium) hydrogen gas jet target. Antihydrogen is made via e^+e^- pair production by a relativistic beam antiproton in the Coulomb field of a proton in the gas jet, followed by capture of the e^+. The process occurs in rare cases in which the e^+ velocity closely matches the antiproton velocity.