Uq(sl^n)U_q(\hat{sl}_n)-analog of the XXZ chain with a boundary

We study $U_q(\hat{sl}_n)$ analog of the XXZ spin chain with a boundary magnetic field h. We construct explicit bosonic formulas of the vacuum vector and the dual vacuum vector with a boundary magnetic field. We derive integral formulas of the correlation functions.Comment: 24 pages, LaTEX2

Spin Fluid Dynamics Observed by Magnetic Fountain Effect and Mechano-Spin Effect in the Ferromagnetic Superfluid 3^3He A1_1 Phase

Systematic observations of the magnetically generated fountain pressure in the superfluid $^3$He A$_1$ have been carried out in a newly built apparatus designed to reduce the effect of thermal gradients. In the same apparatus, mechanical pumping and filtering of polarized nuclear spins were realized by the pneumatic pumping action of an electrostatically actuated membrane. In both experiments, the measured induced pressure was observed to decay at all temperatures where the A$_1$ phase appeared in magnetic fields up to 13 T and liquid pressures between 1 and 29 bar. The inferred spin relaxation rate tended to increase as the low temperature phase boundary with the A$_2$ phase (T$_{C2}$) was approached. The increase in spin relaxation rate near T$_{C2}$ can be explained by the presence of a minority spin condensate in the A$_1$ phase as predicted by Monien and Tewordt and by the application of the Leggett-Takagi theory of spin relaxation in superfluid $^3$He.Comment: 12 pages, 15 figures, to appear in Physical Review

Flavor-oscillation clocks, continuous quantum measurements and a violation of Einstein equivalence principle

The relation between Einstein equivalence principle and a continuous quantum measurement is analyzed in the context of the recently proposed flavor-oscillation clocks, an idea pioneered by Ahluwalia and Burgard (Gen. Rel Grav. Errata 29, 681 (1997)). We will calculate the measurement outputs if a flavor-oscillation clock, which is immersed in a gravitational field, is subject to a continuous quantum measurement. Afterwards, resorting to the weak equivalence principle, we obtain the corresponding quantities in a freely falling reference frame. Finally, comparing this last result with the measurement outputs that would appear in a Minkowskian spacetime it will be found that they do not coincide, in other words, we have a violation of Einstein equivalence principle. This violation appears in two different forms, namely: (i) the oscillation frequency in a freely falling reference frame does not match with the case predicted by general relativity, a feature previously obtained by Ahluwalia; (ii) the probability distribution of the measurement outputs, obtained by an observer in a freely falling reference frame, does not coincide with the results that would appear in the case of a Minkowskian spacetime.Comment: 16 pages, accepted in Mod. Phys. Letts.

Direct CP, T and/or CPT violations in the K^0-\bar{K^0} system - Implications of the recent KTeV results on 2π2\pi decays -

The recent results on the CP violating parameters Re(e'/e) and \Delta\phi = \phi_{00}-\phi_{+-} reported by the KTeV Collaboration are analyzed with a view to constrain CP, T and CPT violations in a decay process. Combining with some relevant data compiled by the Particle Data Group, we find Re(e_2-e_0) = (0.85 +- 3.11)*10^{-4} and Im(e_2-e_0) = (3.2 +- 0.7)*10^{-4}, where Re(e_I) and Im(e_I) represent respectively CP/CPT and CP/T violations in decay of K^0 and \bar{K^0} into a 2\pi state with isospin I.Comment: 7 pages, No figure

Robertson-Walker fluid sources endowed with rotation characterised by quadratic terms in angular velocity parameter

Einstein's equations for a Robertson-Walker fluid source endowed with rotation Einstein's equations for a Robertson-Walker fluid source endowed with rotation are presented upto and including quadratic terms in angular velocity parameter. A family of analytic solutions are obtained for the case in which the source angular velocity is purely time-dependent. A subclass of solutions is presented which merge smoothly to homogeneous rotating and non-rotating central sources. The particular solution for dust endowed with rotation is presented. In all cases explicit expressions, depending sinusoidally on polar angle, are given for the density and internal supporting pressure of the rotating source. In addition to the non-zero axial velocity of the fluid particles it is shown that there is also a radial component of velocity which vanishes only at the poles. The velocity four-vector has a zero component between poles

Iron K-alpha Fluorescent Line Profiles from Spiral Accretion Flows in AGNs

We present 6.4 keV iron K-alpha fluorescent line profiles predicted for a relativistic black hole accretion disk in the presence of a spiral motion in Kerr geometry, the work extended from an earlier literature motivated by recent magnetohydrodynamic (MHD) simulations. The velocity field of the spiral motion, superposed on the background Keplerian flow, results in a complicated redshift distribution in the accretion disk. An X-ray source attributed to a localized flaring region on the black hole symmetry axis illuminates the iron in the disk. The emissivity form becomes very steep because of the light bending effect from the primary X-ray source to the disk. The predicted line profile is calculated for various spiral waves, and we found, regardless of the source height, that: (i) a multiple-peak along with a classical double-peak structure generally appears, (ii) such a multiple-peak can be categorized into two types, sharp sub-peaks and periodic spiky peaks, (iii) a tightly-packed spiral wave tends to produce more spiky multiple peaks, whereas (iv) a spiral wave with a larger amplitude seems to generate more sharp sub-peaks, (v) the effect seems to be less significant when the spiral wave is centrally concentrated, (vi) the line shape may show a drastic change (forming a double-peak, triple-peak or multiple-peak feature) as the spiral wave rotates with the disk. Our results emphasize that around a rapidly-rotating black hole an extremely redshifted iron line profile with a noticeable spike-like feature can be realized in the presence of the spiral wave. Future X-ray observations, from {\it Astro-E2} for example, will have sufficient spectral resolution for testing our spiral wave model which exhibits unique spike-like features.Comment: 30 pages, 10 figures, submitted to ApJ, will be presented at 204th Meeting of AAS in Denve

The magnetic structure of the intermelallic compounds in the cubic Laves phase (C15) crystal

Magnetic structure of intermetallic compounds of rare earth and 3d transition metal with the C15 structure is studied on the basis of the classical Heisenberg model. By making use of the Lyons-Kaplan method, magnetic phase diagram is calculated with respect to the states with the modulation wave vector Q equivalent to [0,0,0] to obtain seven types of spin structure, and their stability is compared with screw structures of Q parallel with [0,0,1], [1,1,0] and [1,1,1]. The stable region of the Q = [0,0,0] states is limited most drastically by the modulation of Q ∥ [1,1,0].Article信州大学理学部紀要 30(1): 7-23(1995)departmental bulletin pape

Stability in Time-Delay Systems: Quiet Standing Case Study

The analysis of linear time-delay systems has attracted much interest in the literature over last five decade. Two types of stability conditions, namely delay-independent which results guarantee stability for arbitrarily large delays and delay-dependent, results take into account the maximum delay that can be tolerated by the system and, thus, are more useful in applications. The stability in general for linear time-delay systems, can be checked exactly only by eigenvalue considerations. When reasonable chosen with intentional delays, case study effects on time-delay of ankle torque on the stability of quiet standing, it can be used to stabilize and improve the close-loop response of these systems

The Baxter's Q-operator for the W-algebra WNW_N

The q-oscillator representation for the Borel subalgebra of the affine symmetry $U_q(sl_N^)$ is presented. By means of this q-oscillator representation, we give the free field realizations of the Baxter's Q-operator $Q_j(t)$, $\bar{Q}_j(t)$ for the W-algebra $W_N$. We give the functional relations of the $T$-$Q$ operators, including the higher-rank generalization of the Baxter's $T$-$Q$ relation.Comment: LaTE