摘要 :
We have calculated the phase diagram and density of states of single-particle excitations of a lattice model of the Coulomb glass. We employ the replica method to average over disorder and then use linked-cluster expansion to obta...
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We have calculated the phase diagram and density of states of single-particle excitations of a lattice model of the Coulomb glass. We employ the replica method to average over disorder and then use linked-cluster expansion to obtain the free energy in the random phase approximation. We find that the system has a transition to an antiferromagnetic phase below a critical disorder. Above the critical disorder, the system has a glassy "independent spin phase" at zero temperature which crosses over to paramagnetic phase as the temperature is increased. In the antiferromagnetic phase, the single-particle excitation density [density of states (DOS)] has a feature including the gap at the Fermi level due to long-range order. To obtain DOS in the glassy phase, we analyze cavity-field equations for local magnetization (occupation). We obtain DOS at nonzero temperatures and find that with temperature the DOS at the Fermi level increases quadratically and the Coulomb gap decreases linearly.
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摘要 :
We consider a network whose nodes are electromagnetic cavities, each coupled to a single three-level atom.
The nodes are connected by optical fibers. Each atom is addressed by a control laser, which along with the cavity
field dri...
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We consider a network whose nodes are electromagnetic cavities, each coupled to a single three-level atom.
The nodes are connected by optical fibers. Each atom is addressed by a control laser, which along with the cavity
field drives atomic transitions. The network can be in the form of chain or two- and three-dimensional arrays of
N cavities connected by NB fibers. Following the work on a two-cavity system by Pellizzari, we find that under
certain conditions the system possesses two kinds of dark states. The first kind are N states corresponding to
atomic excitations at each node and these are our logical states for quantum processing. The second kind are NB
degenerate dark states on pairs of sites connected by a fiber. By manipulating intensities and phases of control
lasers on the cavities, one can pass adiabatically among these dark states due to their degeneracy. This network
operates as an N-level quantum system in which one can generate computationally useful states by protocols
of external controls. We obtain numerical results for small chains and lattices to demonstrate some quantum
operations such as the transport of states across the array, generation of W states, and Fourier-like states.We also
discuss effects of dissipation and limitations of the model.
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摘要 :
This paper studies the phase diagram and the single-particle density of states of a lattice model of the Coulomb glass in three dimensions. For this purpose we calculate the free energy in the random phase approximation using the ...
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This paper studies the phase diagram and the single-particle density of states of a lattice model of the Coulomb glass in three dimensions. For this purpose we calculate the free energy in the random phase approximation using the replica method to average
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摘要 :
We present a "state of the course" report on a core computer science topic: Computer Organization & Architecture. Our report is based on a survey of over 80 faculty, at colleges and universities around the world, who teach this topic. Based on the responses in the survey, we present our conclusions on the confidence levels of faculty in teaching various core components of the topic. We will present our results in the context of the identified core body of knowledge as defined in the Curriculum 2001. These conclusions can be of help to experts who are willing to provide training and/or pedagogical materials in order to assist those with low confidence levels....
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We present a "state of the course" report on a core computer science topic: Computer Organization & Architecture. Our report is based on a survey of over 80 faculty, at colleges and universities around the world, who teach this topic. Based on the responses in the survey, we present our conclusions on the confidence levels of faculty in teaching various core components of the topic. We will present our results in the context of the identified core body of knowledge as defined in the Curriculum 2001. These conclusions can be of help to experts who are willing to provide training and/or pedagogical materials in order to assist those with low confidence levels.
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