The Klein-Gordon and Dirac equations in a semi-infinite lab (x > 0), in the background metric ds = u(x)(−dt + dx) + dy + dz, are investigated. The resulting equations are studied for the special case u(x) = 1+ gx. It is shown that in the case of zero transverse-momentum, the square of the energy eigenvalues of the spin-1/2 particles are less than the squares of the corresponding eigenvalues of ...

We treat the baryon as a composite system made out of a " core " of three quarks (as in the standard quark model) surrounded by a " sea " (of gluons and q ¯ q-pairs) which is specified by its total quantum numbers like flavor, spin and color. Specifically, we assume the sea to be a flavor octet with spin 0 or 1 but no color. The general wavefunction for spin 1/2 baryons with such a sea componen...

We describe the formalism for optimally estimating and controlling both the state of a spin ensemble and a scalar magnetic field with information obtained from a continuous quantum limited measurement of the spin precession due to the field. The full quantum parameter estimation model is reduced to a simplified equivalent representation to which classical estimation and control theory is applie...

Using inelastic neutron scattering and applied fields up to 11.4 T, we have studied the spin dynamics of the Cr7Ni antiferromagnetic ring in the energy window 0.05-1.6 meV. We demonstrate that the external magnetic field induces an avoided crossing (anticrossing) between energy levels with different total-spin quantum numbers. This corresponds to quantum oscillations of the total spin of each m...

We obtain an explicit expression relating the writhing number, W [C], of the quantum path, C, with any value of spin, s, of the particle which sweeps out that closed curve. We consider a fractal approach to the fractional spin particles and , in this way, we make clear a deeper connection between the Gauss-Bonnet theorem with the spin-statistics relation via the concept of Hausdorff dimension, ...

We obtain an explicit expression relating the writhing number, W [C], of the quantum path, C, with any value of spin, s, of the particle which sweeps out that closed curve. We consider a fractal approach to the fractional spin particles and , in this way, we make clear a deeper connection between the Gauss-Bonnet theorem with the spin-statistics relation via the concept of Hausdorff dimension, ...

Fast quantum spin manipulation is needed to design spin-based quantum logic gates and other quantum applications. Here, we construct exact evolution operator of the nitrogen-vacancy-center (NV) spin in diamond under external magnetic fields and investigate the nonadiabatic geometric phases, both cyclic and non-cyclic, in these fast-manipulated NV spin systems. It is believed that the nonadiabat...

This talk will illustrate the benefits offered by QIP with two devices which use quantum entanglement among nuclear spins to perform high-precision measurements: (1) a spin gyroscope that operates by detecting the frequency shift in the spins precession rate in the rotating frame, which is potentially more accurate than mechanical or optical devices; (2) a quantum amplifier which correlates the...

We study two different parametric pumps--one for pumping spin currents, the other for charge currents--in interacting quantum wires. We find that, as a function of pumping frequency, the spin or charge pumped per cycle has a nonuniversal crossover--depending on pumping details--between two universal fixed point values of 0 and twice the electronic spin or charge quantum number. The direction of...

This paper presents an overview of the properties of magnetic insulators, with emphasis on quantum effects. In particular, the consequences of strong quantum fluctuations on the low-energy properties of a number of systems are reviewed: the occurrence of a spin gap in spin-1 chains and other low-dimensional magnets; the presence of low-lying singlet excitations in several frustrated magnets; th...