5,834 research outputs found
Two-dimensional algebro-geometric difference operators
A generalized inverse problem for a two-dimensional difference operator is
introduced. A new construction of the algebro-geometric difference operators of
two types first considered by I.M.Krichever and S.P.Novikov is proposedComment: 11 pages; added references, enlarged introduction, rewritten abstrac
Topological Phenomena in Normal Metals
This paper is devoted to topological phenomena in normal metals with rather
complicated Fermi surface. The results of the article are based on the deep
topological theorems concerning the geometry of non-compact plane sections of
level surfaces of periodic function in 3-dimensional Euclidean space which are
the quasi-classical electron orbits in the presence of homogeneous magnetic
field. The main result is that the observation of electrical conductivity in
strong magnetic fields can reveal such nontrivial topological characteristics
of Fermi surface as integral planes, connected with conductivity tensor and
locally stable under small rotations of magnetic field. This planes are
connected with generic non-closed orbits on the Fermi surface. Some non-generic
situations are also discussed.Comment: 21 pages, 9 Encapsulated Postscript figure
Dynamical Systems, Topology and Conductivity in Normal Metals
New observable integer-valued numbers of the topological origin were revealed
by the present authors studying the conductivity theory of single crystal 3D
normal metals in the reasonably strong magnetic field (). Our
investigation is based on the study of dynamical systems on Fermi surfaces for
the motion of semi-classical electron in magnetic field. All possible
asymptotic regimes are also found for based on the topological
classification of trajectories.Comment: Latex, 51 pages, 14 eps figure
Precision Quantum Hall Resistance Measurement on Epitaxial Graphene Device in Low Magnetic Field
Precision quantum Hall resistance (QHR) measurements were performed on
large-area epitaxial graphene device at low magnetic fields (B = 2 T - 8 T) at
temperature T = 1.5 K. Hall resistance was measured using Cryogenic Current
Comparator resistance bridge with high biasing current Isd = 40 micro ampere.
The results showed that at B = 8 T the relative deviation of Hall resistance
from the expected quantized value h/2e2 is within experimental uncertainty of
3.5 parts in 108 and remained below 0.35 parts per million (ppm) down to B = 3
T
Topological Phenomena in the Real Periodic Sine-Gordon Theory
The set of real finite-gap Sine-Gordon solutions corresponding to a fixed
spectral curve consists of several connected components. A simple explicit
description of these components obtained by the authors recently is used to
study the consequences of this property. In particular this description allows
to calculate the topological charge of solutions (the averaging of the
-derivative of the potential) and to show that the averaging of other
standard conservation laws is the same for all components.Comment: LaTeX, 18 pages, 3 figure
Superconformal spaces and implications for superstrings
We clarify some properties of projective superspace by using a manifestly
superconformal notation. In particular, we analyze the N=2 scalar multiplet in
detail, including its action, and the propagator and its super-Schwinger
parameters. The internal symmetry is taken to be noncompact (after Wick
rotation), allowing boundary conditions that preserve it off shell.
Generalization to N=4 suggests the coset superspace PSU(2,2|4)/OSp(4|4) for the
AdS/CFT superstring.Comment: 19 pages, no figures; v2: fixed sign, added note & reference; v3:
added note & references, version to appear in Physical Review
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