15,864 research outputs found

### The Picard-Fuchs Equations, Monodromies and Instantons in the N=2 Susy Gauge Theories

We construct the Picard-Fuchs equations of the $N=2$ supersymmetric $SU(2)$
gauge theories with $N_f=0,1,3$ matter multiplets. For the $N_f=0$ theory from
the solutions of the Picard-Fuchs equation the monodromy matrices on the
quantum moduli space are determined. We analyze the Seiberg-Witten solutions to
compute monodromies exactly and present the instanton expansion of the periods
for the $N_f=0,3$ theories.Comment: 8pages, latex, no figure

### On the Monodromies of N=2 Supersymmetric Yang-Mills Theory with Gauge Group SO(2n)

We present families of algebraic curves describing the moduli-space of
$N\!=\!2$ supersymmetric Yang-Mills theory with gauge group $SO(2n)$. We test
our curves by computing the weak coupling monodromies and the number of
$N\!=\!1$ vacua.Comment: 14 pages, 5 Postscript figures, LaTeX file, uses epsf.st

### Theory of Coherent $c$-Axis Josephson Tunneling between Layered Superconductors

We calculate exactly the Josephson current for $c$-axis coherent tunneling
between two layered superconductors, each with internal coherent tight-binding
intra- and interlayer quasiparticle dispersions. Our results also apply when
one or both of the superconductors is a bulk material, and include the usually
neglected effects of surface states. For weak tunneling, our results reduce to
our previous results derived using the tunneling Hamiltonian. Our results are
also correct for strong tunneling. However, the $c$-axis tunneling results of
Tanaka and Kashiwaya are shown to be incorrect in any limit. In addition, we
consider the $c$-axis coherent critical current between two identical layered
superconductors twisted an angle $\phi_0$ about the $c$-axis with respect to
each other. Regardless of the order parameter symmetry, our coherent tunneling
results using a tight-binding intralayer quasiparticle dispersion are
inconsistent with the recent $c$-axis twist bicrystal
Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ twist junction experiments of Li {\it et
al.}Comment: 11 pages, 13 figures, submitted to Physical Review

### Embedding Diagrams of the N=2 Superconformal Algebra under Spectral Flow

The embedding diagrams of representations of the N=2 superconformal algebra
with central charge c=3 are given. Some non-unitary representations possess
subsingular vectors that are systematically described. The structure of the
embedding diagrams is largely defined by the spectral flow symmetry. As an
additional consistency check the action of the spectral flow on the characters
is calculated.Comment: 25 pages, LaTeX, 10 figures, examples and references adde

### Rotating Black Branes wrapped on Einstein Spaces

We present new rotating black brane solutions which solve Einstein's
equations with cosmological constant $\Lambda$ in arbitrary dimension $d$. For
negative $\Lambda$, the branes naturally appear in AdS supergravity
compactifications, and should therefore play some role in the AdS/CFT
correspondence. The spacetimes are warped products of a four-dimensional part
and an Einstein space of dimension $d-4$, which is not necessarily of constant
curvature. As a special subcase, the solutions contain the higher dimensional
generalization of the Kerr-AdS metric recently found by Hawking et al.Comment: 11 pages, RevTeX, no figures, thermodynamical discussion and 2
references adde

### Bi_2 Sr_2 CaCu_2 O_{8+delta} Bicrystal c-Axis Twist Josephson Junctions: A New Phase-Sensitive Test of Order Parameter Symmetry

Li {\it et al.} [Phys. Rev. Lett. {\bf 83}, 4160 (1999)] prepared atomically
clean Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ (BSCCO) Josephson junctions between
identical single crystal cleaves stacked and twisted an angle $\phi_0$ about
the c axis. For each bicrystal, the ratio $J_c^J/J_c^S$ of the c-axis twist
junction critical current density to that across either single crystal part is
unity, independent of $\phi_0$ and the ratio $A^J/A^S$ of junction areas. From
extensive theoretical studies involving a variety of tunneling and
superconducting order parameter (OP) forms, we conclude that the results
provide strong evidence for incoherent c-axis tunneling and that the dominant
OP is s-wave for $T\le T_c$. Recently, Takano {\it et al.} [Phys. Rev. B {\bf
65}, 140315(R) (2002)] obtained results from BSCCO whisker twist junctions
which also rule out a pure d-wave OP, but which are surprisingly suggestive of
coherent c-axis tunneling form small Fermi surface hot spots.Comment: 5 pages, 11 figures, invited talk at LT23, to be published in Physica

### On the Quantum Moduli Space of N=2 Supersymmetric Gauge Theories

Families of hyper-elliptic curves which describe the quantum moduli spaces of
vacua of $N=2$ supersymmetric $SO(N_c)$ gauge theories coupled to $N_f$ flavors
of quarks in the vector representation are constructed. The quantum moduli
spaces for $2N_f < N_c-1$ are determined completely by imposing $R$-symmetry,
instanton corrections and the proper classical singularity structure. These
curves are verified by residue calculations. The quantum moduli spaces for
$2N_f\geq N_c-1$ theories are parameterized and their general structure is
worked out using residue calculations. The exact metrics on the quantum moduli
spaces as well as the exact spectrum of stable massive states are derived. The
results presented here together with recent results of Martinec and Warner
provide a natural conjecture for the form of the curves for the other gauge
groups.Comment: 19 page

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