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The geometric phase: Consequences in classical and quantum physics
No full textWhenever a classical or quantum system undergoes a cyclic evolution
governed by a slow change of parameters, it acquires a phase factor: the geometric
phase. Its most common formulations are known as the Aharonov-Bohm phase,
Pancharatnam and Berry phase. Although traditionally attributed to the foundations
of quantum mechanics, the geometric phase has been generalized and has
become increasingly influential in many areas from condensed-matter physics and
optics to high-energy and particle physics and from fluid mechanics to gravity and
cosmology. Interestingly, the geometric phase also offers unique opportunities for
quantum information and computation. In this article, we first review the geometric
phase in a classical context, the Foucault pendulum, and then we discuss one
of the first quantum manifestation
A dynamical probe of superfluidity in one-dimension: The adiabatic quantum pump
Full text linkQuantum pumping as a dynamical probe of the superfluid response of a onedimensional
(1D) quantum fluid is discussed. It is shown that a spatially periodic potential,
oscillating adiabatically in time with frequency !0, acts as a quantum pump inducing a
continuous momentum current from broken spatiotemporal symmetries of the driven potential.
The momentum current generated by the pump is strongly affected by the interactions. It has
a power-law dependence on the frequency and the temperature with the exponent determined
by the interaction. It depends on the phase difference between two umklapp terms of the drive,
providing indication for the effect of quantum phase slips on the decay of superflow. Application
of the results in understanding the superfluid properties of helium confined in nanometer-size
pores or of laser-cooled atoms is briefly discussed
Cooper Pairs Spintronics in Triplet Spin Valves
Full text linkWe study a spin valve with a triplet superconductor spacer intercalated between two ferromagnets with noncollinear magnetizations. We show that the magnetoresistance of the triplet spin valve depends on the relative orientations of the d vector, characterizing the superconducting order parameter, and the magnetization directions of the ferromagnetic layers. For devices characterized by a long superconductor, the effects of a polarized current sustained by Cooper pairs only are observed. In this regime, a supermagnetoresistance effect emerges, and the chiral symmetry of the order parameter of the superconducting spacer is easily recognized. Our findings open new perspectives in designing spintronics devices based on the cooperation of ferromagnetic and triplet correlations
Effective interactions among heavy quasiparticles: Hamiltonian approach in the Kondo lattice limit
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