11,867 research outputs found
Hydrodynamic description of transport in strongly correlated electron systems
We develop a hydrodynamic description of the resistivity and
magnetoresistance of an electron liquid in a smooth disorder potential. This
approach is valid when the electron-electron scattering length is sufficiently
short. In a broad range of temperatures, the dissipation is dominated by heat
fluxes in the electron fluid, and the resistivity is inversely proportional to
the thermal conductivity, . This is in striking contrast with the
Stokes flow, in which the resistance is independent of and
proportional to the fluid viscosity. We also identify a new hydrodynamic
mechanism of spin magnetoresistance
Macroscopic Aharonov--Bohm Effect in Type-I Superconductors
In type-I superconducting cylinders bulk superconductivity is destroyed above
the first critical current. Below the second critical current the `type-I mixed
state' displays fluctuation superconductivity which contributes to the total
current. A magnetic flux on the axis of the cylinder can change the second
critical current by as much as 50 percent so that half a flux quantum can
switch the cylinder from normal conduction to superconductivity: the
Aharonov--Bohm effect manifests itself in macroscopically large resistance
changes of the cylinder.Comment: five pages, one figur
Effective Lagrangian and Topological Interactions in Supersolids
We construct a low-energy effective Lagrangian describing zero-temperature
supersolids. Galilean invariance imposes strict constraints on the form of the
effective Lagrangian. We identify a topological term in the Lagrangian that
couples superfluid and crystalline modes. For small superfluid fractions this
interaction term is dominant in problems involving defects. As an illustration,
we compute the differential cross section of scatterings of low-energy
transverse elastic phonons by a superfluid vortex. The result is
model-independent.Comment: 10 pages, 1 figure; one reference adde
Nonlocal Andreev reflection at high transmissions
We analyze non-local effects in electron transport across three-terminal
normal-superconducting-normal (NSN) structures. Subgap electrons entering
S-electrode from one N-metal may form Cooper pairs with their counterparts
penetrating from another N-metal. This phenomenon of crossed Andreev reflection
-- combined with normal scattering at SN interfaces -- yields two different
contributions to non-local conductance which we evaluate non-perturbatively at
arbitrary interface transmissions. Both these contributions reach their maximum
values at fully transmitting interfaces and demonstrate interesting features
which can be tested in future experiments.Comment: 4 pages, 4 figure
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