15829252
Factorization of analytic representations in the unit disc and number-phase statistics of a quantum harmonic oscillator
The inner - outer part factorization of analytic representations in the unit disc is used for an effective characterization of the number-phase statistical properties of a quantum harmonic oscillator. It is shown that the factorization is intimately connected with the number-phase Weyl semigroup and its properties. In the Barut - Girardello analytic representation the factorization is implemented as a convolution. Several examples are given which demonstrate the physical significance of the factorization and its role for quantum statistics. In particular, we study the effect of phase-space interference on the factorization properties of a superposition state.
27052128
Parity-dependent squeezing of light
A parity-dependent squeezing operator is introduced which imposes different SU(1,1) rotations on the even and odd subspaces of the harmonic oscillator Hilbert space. This operator is used to define parity-dependent squeezed states which exhibit highly non-classical properties such as strong antibunching, quadrature squeezing, strong oscillations in the photon-number distribution, etc. In contrast to the usual squeezed states whose Q and Wigner functions are simply Gaussians, the parity-dependent squeezed states have much more complicated Q and Wigner functions that exhibit an interesting interference in phase space. The generation of these states by parity-dependent quadratic Hamiltonians is also discussed.
118892945
GOVERNING DYNAMICS BY SQUEEZING IN A SYSTEM OF COLD TRAPPED IONS
Department of Physics, Technion–Israel Institute of Technology, Haifa 32000, Israel~Received 4 June 1998!We consider a system of laser-cooled ions in a linear harmonic trap and study the phenomenon of squeezingexchange between their internal and motional degrees of freedom. An interesting relation between the quantumnoise reduction ~squeezing! and the dynamical evolution is found when the internal and motional subsystemsare prepared in properly squeezed ~intelligent! states. Speciﬁcally, the evolution of the system is fully governedby the relative strengths of spectroscopic and motional squeezing, including the phenomenon of total cancel-lation of the interaction when the initial squeezing parameters are equal. @S1050-2947~99!01401-8#PACS number~s!: 03.65.Bz, 42.50.Dv, 42.50.Vk, 32.80.Qk
120468461
Simple non-hermitian choices for the standardization operator in projected perturbation theory
Abstract We suggest simple non-hermitian choices for the Peierls standardization operator and test them in a simplified one-dimensional model of H + 2 .
687385
Nonclassical interferometry with intelligent light.
We study the phase sensitivity of SU(2) and SU(1,1) interferometers fed by two-mode field states which are intelligent states for Hermitian generators of the SU(2) and SU(1,1) groups, respectively. Intelligent states minimize uncertainty relations and this makes possible an essential reduction of the quantum noise in interferometers. Exact closed expressions for the minimum detectable phase shift are obtained in terms of the Jacobi polynomials. These expressions are compared with results for some conventional input states, and some known results for the squeezed input states are reviewed. It is shown that the phase sensitivity for an interferometer that employs squeezing-producing active devices (such as four-wave mixers) should be analyzed in two regimes: (i) fixed input state and variable interferometer, and (ii) fixed interferometer and variable input state. The behavior of the phase sensitivity is essentially different in these two regimes. The use of the SU(2) intelligent states allows us to achieve a phase sensitivity of order $1/\bar{N}$ (where $\bar{N}$ is the total number of photons passing through the phase shifters of the interferometer) without adding four-wave mixers. This avoids the duality in the behavior of the phase sensitivity that occurs for the squeezed input. On the other hand, the SU(1,1) intelligent states have the property of achieving the phase sensitivity of order $1/\bar{N}$ in both regimes.
16820646
Analytic representations based on SU(1,1) coherent states and their applications
We consider two analytic representations of the SU(1,1) Lie group: the representation in the unit disc based on the SU(1,1) Perelomov coherent states and the Barut - Girardello representation based on the eigenstates of the SU(1,1) lowering generator. We show that these representations are related through a Laplace transform. A `weak' resolution of the identity in terms of the Perelomov SU(1,1) coherent states is presented which is valid even when the Bargmann index k is smaller than . Various applications of these results in the context of the two-photon realization of SU(1,1) in quantum optics are also discussed.
122141713
A liquid-scintillator total-absorption hadron calorimeter for the study of neutrino interactions
Abstract We describe the performance of a large-volume liquid-scintillator calorimeter which has been used to measure the total energy of hadrons produced by interactions of neutrinos with nucleons. The resolution of the calorimeter is about 12% rms for incident pions over the energy range 20–150 GeV, and about 15% for neutrino-induced hadron systems in the chosen fiducial volume after corrections for imperfect energy containment.
121860583
Measurement of the neutral-current interactions of high-energy neutrinos and antineutrinos
Measurements of the ..nu.. and nu-bar weak hadronic neutral-current total cross sections and hadron energy distributions are consistent with a V - A form for this current. They are three standard deviations from pure V, pure A, or a pure T form and unambiguously exclude V + A and any linear combination of S and P.
118907734
Separation of the variables in the solar neutrino problem.
120319912
A large-area magnetic spectrometer for the study of high-energy neutrino interactions
Abstract We describe the design, construction, and performance of a large solid iron magnetic spectrometer which has been used to i dentify and measure the momentum of muons produced by interactions of neutrinos with nucleons. The rms momentum resolution varies from 10 to 15 percent between 5 and 150 GeV/ c .
117988119
Observation of weak neutral currents and bare charm in Fermilab experiment 1A
Fermilab experiment 1A, a collaboration of physicists from Harvard, the University of Pennsylvania, and the University of Wisconsin, began taking data early in 1973. It soon observed neutrino‐induced events indicating the existence of a weak neutral current. At the same time, a particle with a new hadronic quantum number was also observed. The story of those observations is told here through the medium of the E‐1A publications of the period.