Noncommutativity in an open string moving in a background Neveu-Schwarz field is investigated in a gauge independent Hamiltonian approach, leading to new results. The noncommutativity is shown to be a direct consequence of the non-trivial boundary conditions, which, contrary to several approaches, are not treated as constraints. We find that the noncommutativity persists for all string points. ...

Noncommutativity in an open string moving in a background Neveu-Schwarz field is investigated in a gauge independent Hamiltonian approach. The noncommutativity is shown to be a direct consequence of the non-trivial boundary conditions, which, contrary to several approaches, are not treated as constraints. We find that the noncommutativity persists for all string points. In the conformal gauge o...

We study the effects of noncommutativity of spacetime geometry on the thermodynamical properties of the de Sitter horizon. We show that noncommutativity results in modifications in temperature, entropy and vacuum energy and that these modifications are of order of the Planck scale, suggesting that the size of the noncommutative parameter should be close to that of the Planck. In an alternative ...

We present a model of Moyal-type noncommutativity with timedepending noncommutativity parameter and the exact gauge invariant action for the U(1) noncommutative gauge theory. We briefly result the results of the analysis of plane-wave propagation in a regime of a small but rapidly changing noncommutativity.

It is known that the noncommutativity of D-brane coordinate is responsible for describing the higher-dimensional D-branes in terms of more fundamental ones such as D-particles or D-instantons, while considering a noncommutative torus as a target space is conjectured to be equivalent to introducing the background antisymmetric tensor field in matrix models. In the present paper we clarify the du...

In this paper we demonstrate that coordinate noncommutativity at short distances can show up in critical phenomena through UV-IR mixing. In the symmetric phase of the Landau-Ginsburg model, noncommutativity is shown to give rise to a non-zero anomalous dimension at one loop, and to cause instability towards a new phase at large noncommutativity. In particular, in less than four dimensions, the ...