6,559 research outputs found
Scalable solid-state quantum processor using subradiant two-atom states
We propose a realization of a scalable, high-performance quantum processor
whose qubits are represented by the ground and subradiant states of effective
dimers formed by pairs of two-level systems coupled by resonant dipole-dipole
interaction. The dimers are implanted in low-temperature solid host material at
controllable nanoscale separations. The two-qubit entanglement either relies on
the coherent excitation exchange between the dimers or is mediated by external
laser fields.Comment: 4 pages, 3 figure
Novel methods of fabrication and metrology of superconducting nanostructures
As metrology extends toward the nanoscale, a number of potential applications and new challenges arise. By combining photolithography with focused ion beam and/or electron beam methods, superconducting quantum interference devices (SQUIDs) with loop dimensions down to 200 nm and superconducting bridge dimensions of the order 80 nm have been produced. These SQUIDs have a range of potential applications. As an illustration, we describe a method for characterizing the effective area and the magnetic penetration depth of a structured superconducting thin film in the extreme limit, where the superconducting penetration depth is much greater than the film thickness and is comparable with the lateral dimensions of the device
Taxonomic revision of Corynotheca (Hemerocallidaceae / Asphodelaceae)
The genus Corynotheca F.Muell. ex Benth. is revised and Corynotheca borealis R.L.Barrett, Keighery & T.Macfarlane is described as a new species from the east Kimberley region of Western Australia and the adjacent Northern Territory. Corynotheca dichotoma (F.Muell.) F.Muell. ex Benth. is reinstated for a species growing on yellow sands in the Mid west of Western Australia. The taxonomic and geographic limits of varieties of C. micrantha (Lindl.) Druce are reconsidered and all are recognised at specific rank. Four new combinations are made: Corynotheca divaricata (R.J.F.Hend.) R.L.Barrett & T.Macfarlane, Corynotheca elongata (R.J.F.Hend.) R.L.Barrett & T.Macfarlane, Corynotheca gracilis (R.J.F.Hend.) R.L.Barrett & T.Macfarlane and Corynotheca panda (R.J.F.Hend.) R.L.Barrett & T.Macfarlane. All are illustrated and a revised key to the thirteen species of Corynotheca recognised is provided
Photon-added coherent states as nonlinear coherent states
The states , defined as up to a
normalization constant and is a nonnegative integer, are shown to be the
eigenstates of where is a nonlinear
function of the number operator . The explicit form of
is constructed. The eigenstates of this operator for negative values of are
introduced. The properties of these states are discussed and compared with
those of the state .Comment: Rev Tex file with two figures as postscript files attached. Email:
[email protected]
Symplectic and orthogonal Lie algebra technology for bosonic and fermionic oscillator models of integrable systems
To provide tools, especially L-operators, for use in studies of rational
Yang-Baxter algebras and quantum integrable models when the Lie algebras so(N)
(b_n, d_n) or sp(2n) (c_n) are the invariance algebras of their R matrices,
this paper develops a presentation of these Lie algebras convenient for the
context, and derives many properties of the matrices of their defining
representations and of the ad-invariant tensors that enter their multiplication
laws. Metaplectic-type representations of sp(2n) and so(N) on bosonic and on
fermionic Fock spaces respectively are constructed. Concise general expressions
(see (5.2) and (5.5) below) for their L-operators are obtained, and used to
derive simple formulas for the T operators of the rational RTT algebra of the
associated integral systems, thereby enabling their efficient treatment by
means of the algebraic Bethe ansatz.Comment: 24 pages, LaTe
Real Forms of the Oscillator Quantum Algebra and its Representations
We consider the conditions under which the -oscillator algebra becomes a
Hopf -algebra. In particular, we show that there are at least two real forms
associated with the algebra. Furthermore, through the representations, it is
shown that they are related to with different
conjugations.Comment: 10 pages, Ams-Tex, To be published in Letters in Mathematical physic
Quantum Field Theory with Nonzero Minimal Uncertainties in Positions and Momenta
A noncommutative geometric generalisation of the quantum field theoretical
framework is developed by generalising the Heisenberg commutation relations.
There appear nonzero minimal uncertainties in positions and in momenta. As the
main result it is shown with the example of a quadratically ultraviolet
divergent graph in theory that nonzero minimal uncertainties in
positions do have the power to regularise. These studies are motivated with the
ansatz that nonzero minimal uncertainties in positions and in momenta arise
from gravity. Algebraic techniques are used that have been developed in the
field of quantum groups.Comment: 52 pages LATEX, DAMTP/93-33. Revised version now includes a chapter
on the Poincare algebra and curvature as noncommutativity of momentum spac
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