3,102 research outputs found

    Topology Change for Fuzzy Physics: Fuzzy Spaces as Hopf Algebras

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    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

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    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 SNS_N. 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

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    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 S4S^4 on which states cannot be localised, but which fluctuate into other manifolds like CP3 CP^3 . 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 CPTCPT 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

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    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

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    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

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    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

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    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 Bχn\mathcal{B}_{\chi\vec{n}} different from the Moyal plane. We argue that it quantizes time in units of χ\chi. Energy is then conserved only mod 2πχ\frac{2\pi}{\chi}. 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

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    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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