3,076 research outputs found
Vortex core transitions in superfluid 3He in globally anisotropic aerogels
Core structures of a single vortex in A-like and B-like phases of superfluid
3He in uniaxially compressed and stretched aerogels are studied by numerically
solving Ginzburg-Landau equations derived microscopically. It is found that,
although any uniaxial deformation leads to a wider A-like phase with the axial
pairing in the pressure-temperature phase diagram, the vortex core states in
the two phases in aerogel depend highly on the type of deformation. In a
compressed aerogel, the first-order vortex core transition (VCT) previously
seen in the bulk B phase appears at any pressure in the B-like phase while no
strange vortex core is expected in the corresponding A-like phase. By contrast,
in a stretched aerogel, the VCT in the B-like phase is lost while another VCT
is expected to occur between a nonunitary core and a polar one in the A-like
phase. Experimental search for these results is hoped to understand correlation
between superfluid 3He and aerogel structure.Comment: 7 pages, 6 figures Text was changed. Resubmitted versio
The Whitham Deformation of the Dijkgraaf-Vafa Theory
We discuss the Whitham deformation of the effective superpotential in the
Dijkgraaf-Vafa (DV) theory. It amounts to discussing the Whitham deformation of
an underlying (hyper)elliptic curve. Taking the elliptic case for simplicity we
derive the Whitham equation for the period, which governs flowings of branch
points on the Riemann surface. By studying the hodograph solution to the
Whitham equation it is shown that the effective superpotential in the DV theory
is realized by many different meromorphic differentials. Depending on which
meromorphic differential to take, the effective superpotential undergoes
different deformations. This aspect of the DV theory is discussed in detail by
taking the N=1^* theory. We give a physical interpretation of the deformation
parameters.Comment: 35pages, 1 figure; v2: one section added to give a physical
interpretation of the deformation parameters, one reference added, minor
corrections; v4: minor correction
Fermions at unitarity and Haldane Exclusion Statistics
We consider a gas of neutral fermionic atoms at ultra-low temperatures, with
the attractive interaction tuned to Feshbach resonance. We calculate, the
variation of the chemical potential and the energy per particle as a function
of temperature by assuming the system to be an ideal gas obeying the Haldane-Wu
fractional exclusion statistics. Our results for the untrapped gas compare
favourably with the recently published Monte Carlo calculations of two groups.
For a harmonically trapped gas, the results agree with experiment, and also
with other published work.Comment: 4 pages, 1 postscript figur
Testing new physics with the electron g-2
We argue that the anomalous magnetic moment of the electron (a_e) can be used
to probe new physics. We show that the present bound on new-physics
contributions to a_e is 8*10^-13, but the sensitivity can be improved by about
an order of magnitude with new measurements of a_e and more refined
determinations of alpha in atomic-physics experiments. Tests on new-physics
effects in a_e can play a crucial role in the interpretation of the observed
discrepancy in the anomalous magnetic moment of the muon (a_mu). In a large
class of models, new contributions to magnetic moments scale with the square of
lepton masses and thus the anomaly in a_mu suggests a new-physics effect in a_e
of (0.7 +- 0.2)*10^-13. We also present examples of new-physics theories in
which this scaling is violated and larger effects in a_e are expected. In such
models the value of a_e is correlated with specific predictions for processes
with violation of lepton number or lepton universality, and with the electric
dipole moment of the electron.Comment: 34 pages, 7 figures. Minor changes and references adde
Improving the Feeding Value of Cotton Stalk, Wheat Straw and Rice Straw with Ozonation
The experiment was conducted to study the effect of ozone treatment on the feed value of cotton stalk, wheat straw and rice straw. These feeds were cut into 2 cm and 4 cm lengths, and rolled before ozonizing. The ozonizing periods were 30 min. 60min and. 120 min. The Acid Detergent Lignin (ADL) concentration of the feeds decreased with ozone treatment. Except for rice straw, the short cutting treatment (2cm) decreased the concentration of ADL and Cellulose of the ozonized cotton stalk and wheat straw. Rolling and ozone treatment were effective in decreasing the ADL concentration of cotton stalk. IVDMD (In Vitro Dry Matter Digestibility) of feeds rose 17 points in the cotton stalk, 4 points in the wheat straw and the rice straw with ozonizing. The short cut (2cm) cotton stalk and the wheat straw showed an increase in IVDMD but the rice straw showed no change. Rolled and ozonized cotton stalk was the only feed to show a rise in IVDMD. The concentration of ADL and Hemicellulose of all feeds decreased with ozonation but the IVDMD was related to the decrease in the contents of ADL of feeds. The higher ADL concentration in the feeds, higher the ozonation effect
Logarithmic deformations of the rational superpotential/Landau-Ginzburg construction of solutions of the WDVV equations
The superpotential in the Landau-Ginzburg construction of solutions to the Witten-Dijkgraaf-Verlinde-Verlinde (or WDVV) equations is modified to include logarithmic terms. This results in deformations - quadratic in the deformation parameters- of the normal prepotential solutions of the WDVV equations. Such solutions satisfy various pseudo-quasi-homogeneity conditions, on assigning a notional weight to the deformation parameters. These solutions originate in the so-called `water-bag' reductions of the dispersionless KP hierarchy. This construction includes, as a special case, deformations which are polynomial in the flat coordinates, resulting in a new class of polynomial solutions of the WDVV equations
Systematic study of the SO(10) symmetry breaking vacua in the matrix model for type IIB superstrings
We study the properties of the space-time that emerges dynamically from the
matrix model for type IIB superstrings in ten dimensions. We calculate the free
energy and the extent of space-time using the Gaussian expansion method up to
the third order. Unlike previous works, we study the SO(d) symmetric vacua with
all possible values of d within the range , and observe clear
indication of plateaus in the parameter space of the Gaussian action, which is
crucial for the results to be reliable. The obtained results indeed exhibit
systematic dependence on d, which turns out to be surprisingly similar to what
was observed recently in an analogous work on the six-dimensional version of
the model. In particular, we find the following properties: i) the extent in
the shrunken directions is given by a constant, which does not depend on d; ii)
the ten-dimensional volume of the Euclidean space-time is given by a constant,
which does not depend on d except for d = 2; iii) The free energy takes the
minimum value at d = 3. Intuitive understanding of these results is given by
using the low-energy effective theory and some Monte Carlo results.Comment: 33 pages, 10 figures; minor corrections, reference added. arXiv admin
note: substantial text overlap with arXiv:1007.088
Inhomogeneous superconducting states of mesoscopic thin-walled cylinders in external magnetic fields
We theoretically investigate the appearance of spatially modulated superconducting states in mesoscopic superconducting thin-wall cylinders in a magnetic field at low temperatures. Quantization of the electron motion around the circumference of the cylinder leads to a discontinuous evolution of the spatial modulation of the superconducting order parameter along the transition line Tc(H). We show that this discontinuity leads to the nonmonotonic behavior of the specific heat jump at the onset of superconductivity as a function of temperature and field. We argue that this geometry provides an excellent opportunity to directly and unambiguously detect distinctive signatures of the Fulde-Ferrell-Larkin-Ovchinnikov modulation of the superconducting order. © 2013 American Physical Society
Topological Landau-Ginzburg theory with a rational potential and the dispersionless KP hierarchy
Based on the dispersionless KP (dKP) theory, we give a comprehensive study of
the topological Landau-Ginzburg (LG) theory characterized by a rational
potential. Writing the dKP hierarchy in a general form, we find that the
hierarchy naturally includes the dispersionless (continuous) limit of Toda
hierarchy and its generalizations having finite number of primaries. Several
flat solutions of the topological LG theory are obtained in this formulation,
and are identified with those discussed by Dubrovin. We explicitly construct
gravitational descendants for all the primary fields. Giving a residue formula
for the 3-point functions of the fields, we show that these 3-point functions
satisfy the topological recursion relation. The string equation is obtained as
the generalized hodograph solutions of the dKP hierarchy, which show that all
the gravitational effects to the constitutive equations (2-point functions) can
be renormalized into the coupling constants in the small phase space.Comment: 54 pages, Plain TeX. Figure could be obtained from Kodam
Fluctuation and Order of Antiferromagnetism induced by Paramagnetic Pair-Breaking in Superconducting Vortex Lattice
Effects of the strong Pauli-paramagnetic pair-breaking (PPB) on the vortex
lattice in d-wave superconductors are theoretically studied by putting emphasis
on consequences of the PPB-induced antiferromagnetic (AFM) ordering in the
spatial modulation in the vortex lattice. It is shown that the PPB-induced AFM
fluctuation in the superconducting state leads to an enhancement of the vortex
lattice form factor which is a measure of spatial variations of the internal
magnetic field and that the enhancement becomes more remarkable as an AFM
instability is approached. It is also demonstrated that the PPB-induced AFM
ordering is assisted by the vortex-lattice modulation, and thus, that the
resulting AFM order is spatially modulated, while it is not localized in the
vortex cores but coexistent with the nonvanishing superconducting order
parameter. These results are discussed in connection with two phenomena
observed in CeCoIn5, the anomalous field dependence of the vortex lattice form
factor and the AFM order appearing inside the high-field and low-temperature
superconducting phase.Comment: 26 pages, 13 figure
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