3,102 research outputs found
Topology Change for Fuzzy Physics: Fuzzy Spaces as Hopf Algebras
Fuzzy spaces are obtained by quantizing adjoint orbits of compact semi-simple
Lie groups. Fuzzy spheres emerge from quantizing S^2 and are associated with
the group SU(2) in this manner. They are useful for regularizing quantum field
theories and modeling spacetimes by non-commutative manifolds. We show that
fuzzy spaces are Hopf algebras and in fact have more structure than the latter.
They are thus candidates for quantum symmetries. Using their generalized Hopf
algebraic structures, we can also model processes where one fuzzy space splits
into several fuzzy spaces. For example we can discuss the quantum transition
where the fuzzy sphere for angular momentum J splits into fuzzy spheres for
angular momenta K and L.Comment: LaTeX, 13 pages, v3: minor additions, added references, v4: corrected
typos, to appear in IJMP
Quantum Geons and Noncommutative Spacetimes
Physical considerations strongly indicate that spacetime at Planck scales is
noncommutative. A popular model for such a spacetime is the Moyal plane. The
Poincar\`e group algebra acts on it with a Drinfel'd-twisted coproduct. But the
latter is not appropriate for more complicated spacetimes such as those
containing the Friedman-Sorkin (topological) geons. They have rich
diffeomorphism groups and in particular mapping class groups, so that the
statistics groups for N identical geons is strikingly different from the
permutation group . We generalise the Drinfel'd twist to (essentially)
generic groups including to finite and discrete ones and use it to modify the
commutative spacetime algebras of geons as well to noncommutative algebras. The
latter support twisted actions of diffeos of geon spacetimes and associated
twisted statistics. The notion of covariant fields for geons is formulated and
their twisted versions are constructed from their untwisted versions.
Non-associative spacetime algebras arise naturally in our analysis. Physical
consequences, such as the violation of Pauli principle, seem to be the outcomes
of such nonassociativity.
The richness of the statistics groups of identical geons comes from the
nontrivial fundamental groups of their spatial slices. As discussed long ago,
extended objects like rings and D-branes also have similar rich fundamental
groups. This work is recalled and its relevance to the present quantum geon
context is pointed out.Comment: 41 page
Quantum Spacetimes in the Year 1
We review certain emergent notions on the nature of spacetime from
noncommutative geometry and their radical implications. These ideas of
spacetime are suggested from developments in fuzzy physics, string theory, and
deformation quantisation. The review focuses on the ideas coming from fuzzy
physics. We find models of quantum spacetime like fuzzy on which states
cannot be localised, but which fluctuate into other manifolds like .
New uncertainty principles concerning such lack of localisability on quantum
spacetimes are formulated.Such investigations show the possibility of
formulating and answering questions like the probabilty of finding a point of a
quantum manifold in a state localised on another one. Additional striking
possibilities indicated by these developments is the (generic) failure of
theorem and the conventional spin-statistics connection. They even suggest that
Planck's `` constant '' may not be a constant, but an operator which does not
commute with all observables. All these novel possibilities arise within the
rules of conventional quantum physics,and with no serious input from gravity
physics.Comment: 11 pages, LaTeX; talks given at Utica and Kolkata .Minor corrections
made and references adde
Duality in Fuzzy Sigma Models
Nonlinear `sigma' models in two dimensions have BPS solitons which are
solutions of self- and anti-self-duality constraints. In this paper, we find
their analogues for fuzzy sigma models on fuzzy spheres which were treated in
detail by us in earlier work. We show that fuzzy BPS solitons are quantized
versions of `Bott projectors', and construct them explicitly. Their
supersymmetric versions follow from the work of S. Kurkcuoglu.Comment: Latex, 9 pages; misprints correcte
Waves on Noncommutative Spacetimes
Waves on ``commutative'' spacetimes like R^d are elements of the commutative
algebra C^0(R^d) of functions on R^d. When C^0(R^d) is deformed to a
noncommutative algebra {\cal A}_\theta (R^d) with deformation parameter \theta
({\cal A}_0 (R^d) = C^0(R^d)), waves being its elements, are no longer
complex-valued functions on R^d. Rules for their interpretation, such as
measurement of their intensity, and energy, thus need to be stated. We address
this task here. We then apply the rules to interference and diffraction for d
\leq 4 and with time-space noncommutativity. Novel phenomena are encountered.
Thus when the time of observation T is so brief that T \leq 2 \theta w, where w
is the frequency of incident waves, no interference can be observed. For larger
times, the interference pattern is deformed and depends on \frac{\theta w}{T}.
It approaches the commutative pattern only when \frac{\theta w}{T} goes to 0.
As an application, we discuss interference of star light due to cosmic strings.Comment: 19 pages, 5 figures, LaTeX, added references, corrected typo
EVALUATION OF PALM OIL BASED FATTY ACIDS FOR SYNTHESIS OF EMULSIFIER IN DRILLING FLUIDS
Drilling mud play a major role in the process of drilling and production and one of its main functions is to provide hydrostatic pressure to prevent kick. Drilling fluids could be categorised as oil based mud and water based mud. The oil based mud functionality outweighs the functionality of water based mud though oil based mud requires emulsifying agent to provide stability to it. This project titled: THE USAGE OF PALM OIL BASED FATTY ACIDS AS AN EMULSIFYING AGENT FOR DRILLING FLUIDS is to determine the ability of emulsifying agent, under high pressure and high temperature, to maintain the stability of oil based mud under high pressure and high temperature. This research will be a stepping stone for future research of the potential drilling fluid additives which is obtainable from abundant local resources. The potential usage of palm products from Malaysia as an emulsifying agent for drilling fluids is still in the experimental stage though it has high potential. Through my research I wish to look into the potential of palm oil based fatty acids able to compete with other non-biodegradable products. The problems caused by using current type emulsifier is mostly due to the nature of the product which does not decompose naturally and may cause a significant impact on the environment if proper treatment is not made before disposal. Other than that, concerning the cost of importing the product which is considerably high. This project involves a lot of lab work and experiments in order to test the effectiveness of the product and could potentially help to identify the optimization usage of palm oil based fatty acids as emulsifying agent for drilling fluids used in drilling operation. The main properties that will be investigated are the emulsion stability, plastic viscosity, yield point, gel strength and HTHP of the mud with the new emulsifier. The test results shows some interesting results in favour of the new emulsifier and will be explained in depth in the results and discussion part
Non-Pauli Effects from Noncommutative Spacetimes
Noncommutative spacetimes lead to nonlocal quantum field theories (qft's)
where spin-statistics theorems cannot be proved. For this reason, and also
backed by detailed arguments, it has been suggested that they get corrected on
such spacetimes leading to small violations of the Pauli principle. In a recent
paper \cite{Pauli}, Pauli-forbidden transitions from spacetime noncommutativity
were calculated and confronted with experiments. Here we give details of the
computation missing from this paper. The latter was based on a spacetime
different from the Moyal plane. We argue that it
quantizes time in units of . Energy is then conserved only mod
. Issues related to superselection rules raised by non-Pauli
effects are also discussed in a preliminary manner.Comment: 15 Pages, 1 Table, Full details and further developments of
arXiv:1003.2250. This version is close to the one accepted by JHE
Interacting Quantum Topologies and the Quantum Hall Effect
The algebra of observables of planar electrons subject to a constant
background magnetic field B is given by A_theta(R^2) x A_theta(R^2) the product
of two mutually commuting Moyal algebras. It describes the free Hamiltonian and
the guiding centre coordinates. We argue that A_theta(R^2) itself furnishes a
representation space for the actions of these two Moyal algebras, and suggest
physical arguments for this choice of the representation space. We give the
proper setup to couple the matter fields based on A_theta(R^2) to
electromagnetic fields which are described by the abelian commutative gauge
group G_c(U(1)), i.e. gauge fields based on A_0(R^2). This enables us to give a
manifestly gauge covariant formulation of integer quantum Hall effect (IQHE).
Thus, we can view IQHE as an elementary example of interacting quantum
topologies, where matter and gauge fields based on algebras A_theta^prime with
different theta^prime appear. Two-particle wave functions in this approach are
based on A_theta(R^2) x A_theta(R^2). We find that the full symmetry group in
IQHE, which is the semi-direct product SO(2) \ltimes G_c(U(1)) acts on this
tensor product using the twisted coproduct Delta_theta. Consequently, as we
show, many particle sectors of each Landau level have twisted statistics. As an
example, we find the twisted two particle Laughlin wave functions.Comment: 10 pages, LaTeX, Corrected typos, Published versio
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