15,389 research outputs found
High Dynamic-Range and Very Low Noise K-Band p-HEMT LNA MMIC for LMDS and Satellite Communication
An excellent noise figure and high linearity, K-band p-HEMT LNA MMIC, that incorporates single-bias configuration and negative feedback circuit, has be en developed for LMDS (Local Multi-point Distribution Service) and satellite communication. The third order intercept point (IP3) of this MMIC is 20 dBm, while output power at 1-dB gain compression is 8.5 dBm. The IP3 and noise figure is 19.5 +/- 1 dBm and 1.8 +/- 0.2 dB, respectively, at frequencies between 24 and 32 GHz. The die size of the MMIC is 1.9 mm. This MMIC shows a potential reliable application in high-speed wireless access system
Zero-field and Larmor spinor precessions in a neutron polarimeter experiment
We present a neutron polarimetric experiment where two kinds of spinor
precessions are observed: one is induced by different total energy of neutrons
(zero-field precession) and the other is induced by a stationary guide field
(Larmor precession). A characteristic of the former is the dependence of the
energy-difference, which is in practice tuned by the frequency of the
interacting oscillating magnetic field. In contrast the latter completely
depends on the strength of the guide field, namely Larmor frequency. Our
neutron-polarimetric experiment exhibits individual tuning as well as specific
properties of each spinor precession, which assures the use of both spin
precessions for multi-entangled spinor manipulation.Comment: 12 pages, 4 figure
Superconductivity of Quasi-One-Dimensional Electrons in Strong Magnetic Field
The superconductivity of quasi-one-dimensional electrons in the magnetic
field is studied. The system is described as the one-dimensional electrons with
no frustration due to the magnetic field. The interaction is assumed to be
attractive between electrons in the nearest chains, which corresponds to the
lines of nodes of the energy gap in the absence of the magnetic field. The
effective interaction depends on the magnetic field and the transverse
momentum. As the magnetic field becomes strong, the transition temperature of
the spin-triplet superconductivity oscillates, while that of the spin-singlet
increases monotonically.Comment: 15 pages, RevTeX, 3 PostScript figures in uuencoded compressed tar
file are appende
Noncyclic Pancharatnam phase for mixed state SU(2) evolution in neutron polarimetry
We have measured the Pancharatnam relative phase for spin-1/2 states. In a
neutron polarimetry experiment the minima and maxima of intensity modulations,
giving the Pancharatnam phase, were determined. We have also considered general
SU(2) evolution for mixed states. The results are in good agreement with
theory.Comment: 5 pages, 4 figures, to be published in Phys.Lett.
Mott Transition in the Two-Dimensional Flux Phase
Effects of the electron-electron interaction in the two-dimensional flux
phase are investigated. We treat the half-filled Hubbard model with a magnetic
flux per plaquette by the quantum Monte Carlo method. When the
interaction is small, an antiferromagnetic long-range does not exist and the
charge fluctuation is different from that of the Mott insulator It suggests
that the Mott transition occurs at finite strength of the interaction in the
flux phase, which is in contrast to the standard Hubbard model.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Let
The Metal-Insulator Transition in the Doubly Degenerate Hubbard Model
A systematic study has been made on the metal-insulator (MI) transition of
the doubly degenerate Hubbard model (DHM) in the paramagnetic ground state, by
using the slave-boson mean-field theory which is equivalent to the Gutzwiller
approximation (GA). For the case of infinite electron-electron interactions, we
obtain the analytic solution, which becomes exact in the limit of infinite
spatial dimension. On the contrary, the finite-interaction case is investigated
by numerical methods with the use of the simple-cubic model with the
nearest-neighbor hopping. The mass-enhancement factor, , is shown to
increase divergently as one approaches the integer fillings (), at
which the MI transition takes place, being the total number of electrons.
The calculated dependence of is compared with the observed
specific-heat coefficient, , of which is reported
to significantly increase as approaches unity.Comment: Latex 16 pages, 10 ps figures included, published in J. Phys. Soc.
Jpn. with some minor modifications. ([email protected]
Violation of Bell-like Inequality for spin-energy entanglement in neutron polarimetry
Violation of a Bell-like inequality for a spin-energy entangled neutron state
has been confirmed in a polarimetric experiment. The proposed inequality, in
Clauser-Horne-Shimony-Holt (CHSH) formalism, relies on correlations between the
spin and energy degree of freedom in a single-neutron system. The entangled
states are generated utilizing a suitable combination of two radio-frequency
fields in a neutron polarimeter setup. The correlation function S is determined
to be 2.333+/-0.005, which violates the Bell-like CHSH inequality by more than
66 standard deviations.Comment: 4 pages 2 figure
Roles of proton-neutron interactions in alpha-like four-nucleon correlations
An extended pairing plus QQ force model, which has been shown to successfully
explain the nuclear binding energy and related quantities such as the symmetry
energy, is applied to study the alpha-like four-nucleon correlations in
1f_{7/2} shell nuclei.
The double difference of binding energies, which displays a characteristic
behavior at , is interpreted in terms of the alpha-like
correlations. Important roles of proton-neutron interactions forming the
alpha-like correlated structure are discussed.Comment: 10 pages, 2 figures, RevTex, submitted to Phys. Rev.
- …