25 research outputs found
Dual families of non-commutative quantum systems
We demonstrate how a one parameter family of interacting non-commuting
Hamiltonians, which are physically equivalent, can be constructed in
non-commutative quantum mechanics. This construction is carried out exactly (to
all orders in the non-commutative parameter) and analytically in two dimensions
for a free particle and a harmonic oscillator moving in a constant magnetic
field. We discuss the significance of the Seiberg-Witten map in this context.
It is shown for the harmonic oscillator potential that an approximate duality,
valid in the low energy sector, can be constructed between the interacting
commutative and a non-interacting non-commutative Hamiltonian. This
approximation holds to order 1/B and is therefore valid in the case of strong
magnetic fields and weak Landau-level mixing.Comment: 11 pages, no figure
Twisted Galilean symmetry and the Pauli principle at low energies
We show the twisted Galilean invariance of the noncommutative parameter, even
in presence of space-time noncommutativity. We then obtain the deformed algebra
of the Schr\"odinger field in configuration and momentum space by studying the
action of the twisted Galilean group on the non-relativistic limit of the
Klein-Gordon field. Using this deformed algebra we compute the two particle
correlation function to study the possible extent to which the previously
proposed violation of the Pauli principle may impact at low energies. It is
concluded that any possible effect is probably well beyond detection at current
energies.Comment: 16 pages Latex, 2 figures Some modifications made in the abstract,
introduction, typographical errors correcte
Seiberg-Witten map and Galilean symmetry violation in a non-commutative planar system
An effective U(1) gauge invariant theory is constructed for a non-commutative
Schrodinger field coupled to a background U(1)_{\star} gauge field in
2+1-dimensions using first order Seiberg-Witten map. We show that this
effective theory can be cast in the form of usual Schrodinger action with
interaction terms of noncommutative origin provided the gauge field is of
``background'' type with constant magnetic field. The Galilean symmetry is
investigated and a violation is found in the boost sector. We also consider the
problem of Hall conductivity in this framework.Comment: REVTeX, 4 pages, Title changed, Paper shortened, Appendix removed, A
new section on Galilean symmetry adde
A Co-Training Model with Label Propagation on a Bipartite Graph to Identify Online Users with Disabilities
Collecting data from representative users with disabilities for accessibility research is time and resource consuming. With the proliferation of social media websites, many online spaces have emerged for people with disabilities. The information accumulated in such places is of great value for data collection and participant recruiting. However, there are also many active non-representative users in such online spaces such as medical practitioners, caretakers, or family members. In this work, we introduce a novel co-training model based on the homophily phenomenon observed among online users with the same disability. The model combines a variational label propagation algorithm and a naive Bayes classifier to identify online users who have the same disability. We evaluated this model on a dataset collected from Reddit and the results show improvements over traditional models
Strings in pp-wave background and background B-field from membrane and its symplectic quantization
The symplectic quantization technique is applied to open free membrane and
strings in pp-wave background and background gauge field obtained by
compactifying the open membrane in the presence of a background anti-symmetric
3--form field. In both cases, first the Poisson brackets among the Fourier
modes are obtained and then the Poisson brackets among the membrane(string)
coordinates are computed. The full noncommutative phase-space structure is
reproduced in case of strings in pp-wave background and background gauge field.
We feel that this method of obtaining the Poisson algebra is more elegant than
previous approaches discussed in the literature.Comment: Accepted in Physics Letters B, some minor corrections mad
Non(anti) commutativity for open superstrings
Non(anti)commutativity in an open free superstring and also one moving in a
background anti-symmetric tensor field is investigated. In both cases, the
non(anti)commutativity is shown to be a direct consequence of the non-trivial
boundary conditions which, contrary to several approaches, are not treated as
constraints. The above non(anti)commutative structures lead to new results in
the algebra of super constraints which still remain involutive, indicating the
internal consistency of our analysis.Comment: 10 pages Latex, To appear in Physics Letters
Voros product and the Pauli principle at low energies
Using the Voros star product, we investigate the status of the two particle
correlation function to study the possible extent to which the previously
proposed violation of the Pauli principle may impact at low energies. The
results show interesting features which are not present in the computations
made using the Moyal star product.Comment: 5 pages LateX, minor correction
String non(anti)commutativity for Neveu-Schwarz boundary conditions
The appearance of non(anti)commutativity in superstring theory, satisfying
the Neveu-Schwarz boundary conditions is discussed in this paper. Both an open
free superstring and also one moving in a background antisymmetric tensor field
are analyzed to illustrate the point that string non(anti)commutativity is a
consequence of the nontrivial boundary conditions. The method used here is
quite different from several other approaches where boundary conditions were
treated as constraints. An interesting observation of this study is that, one
requires that the bosonic sector satisfies Dirichlet boundary conditions at one
end and Neumann at the other in the case of the bosonic variables
being antiperiodic. The non(anti)commutative structures derived in this paper
also leads to the closure of the super constraint algebra which is essential
for the internal consistency of our analysis.Comment: new references added, original article appeared in Int.J.Theor.Phy
The Cannabis sativa genetics and therapeutics relationship network: automatically associating cannabis-related genes to therapeutic properties through chemicals from cannabis literature
Abstract Background Understanding the genome of Cannabis sativa holds significant scientific value due to the multi-faceted therapeutic nature of the plant. Links from cannabis gene to therapeutic property are important to establish gene targets for the optimization of specific therapeutic properties through selective breeding of cannabis strains. Our work establishes a resource for quickly obtaining a complete set of therapeutic properties and genes associated with any known cannabis chemical constituent, as well as relevant literature. Methods State-of-the-art natural language processing (NLP) was used to automatically extract information from many cannabis-related publications, thus producing an undirected multipartite weighted-edge paragraph co-occurrence relationship network composed of two relationship types, gene-chemical and chemical property. We also developed an interactive application to visualize sub-graphs of manageable size. Results Two hundred thirty-four cannabis constituent chemicals, 352 therapeutic properties, and 124 genes from the Cannabis sativa genome form a multipartite network graph which transforms 29,817 cannabis-related research documents from PubMed Central into an easy to visualize and explore network format. Conclusion Use of our network replaces time-consuming and labor intensive manual extraction of information from the large amount of available cannabis literature. This streamlined information retrieval process will enhance the activities of cannabis breeders, cannabis researchers, organic biochemists, pharmaceutical researchers and scientists in many other disciplines