30,564 research outputs found
Constant curvature solutions of Grassmannian sigma models: (1) Holomorphic solutions
We present a general formula for the Gaussian curvature of curved holomorphic
2-spheres in Grassmannian manifolds G(m, n). We then show how to construct such
solutions with constant curvature. We also make some relevant conjectures for
the admissible constant curvatures in G(m, n) and give some explicit
expressions, in particular, for G(2, 4) and G(2, 5).Comment: 14 page
Heat conductivity in linear mixing systems
We present analytical and numerical results on the heat conduction in a
linear mixing system. In particular we consider a quasi one dimensional channel
with triangular scatterers with internal angles irrational multiples of pi and
we show that the system obeys Fourier law of heat conduction. Therefore
deterministic diffusion and normal heat transport which are usually associated
to full hyperbolicity, actually take place in systems without exponential
instability.Comment: Revtex, 4 pages, 6 EPS figure
Weak Measurement of Qubit Oscillations with Strong Response Detectors: Violation of the Fundamental Bound Imposed on Linear Detectors
We investigate the continuous weak measurement of a solid-state qubit by
single electron transistors in nonlinear response regime. It is found that the
signal-to-noise ratio can violate the universal upper bound imposed quantum
mechanically to any linear response detectors. We understand the violation by
means of the cross-correlation of the detector currents.Comment: 4 pages, 4 figure
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