arXiv subjects
Publications and source records attributed to Corneliu Sochichiu.
Matrix models and their connections to String Theory and noncommutative geometry are discussed. Various types of matrix models are reviewed. Most of interest are IKKT and BFSS models. They are introduced as 0+0 and 1+0 dimensional reduction of Yang--Mills model respectively. They are obtained via the deformations of string/membrane worldsheet/worldvolume. Classical solutions leading to noncommutative gauge models are considered.
We search for the possibility to have supersymmetric string bits at finite discretization $J$. From a general setup we find that the string bits can be made supersymmetric modulo a single defect mode which is not expected to have any sensible effect in the continuum limit.
We discuss the continuum limits of Berenstein-Maldacena-Nastase matrix model. They give rise to Poisson bracket gauge field theories on the ordinary two sphere or on a set of two spheres with a gauge groups U(n) depending on the degeneracy of the classical solution about which the model is considered. We show that these models fail to be equivalent among each other in the continuum limit.
We show that the string bit model suffers from doubling in the fermionic sector. The doubling leads to strong violation of supersymmetry in the limit $N\to\infty$. Since there is an exact correspondence between string bits and the algebra of BMN operators even at finite $N$, doubling is expected also on the side of super-Yang--Mills theory. We discuss the origin of the doubling in the BMN sector.
We propose an ansatz for the equations of motion of the noncommutative model of a tachyonic scalar field interacting with a gauge field, which allows one to find time-dependent solutions describing decaying solitons. These correspond to the collapse of lower dimensional branes obtained through tachyon condensation of unstable brane systems in string theory.
We study the equivalence/duality between various non-commutative gauge models at the classical and quantum level. The duality is realised by a linear Seiberg-Witten-like map. The infinitesimal form of this map is analysed in more details.
The role of the gauge invariance in noncommutative field theory is discussed. A basic introduction to noncommutative geometry and noncommutative field theory is given. Background invariant formulation of Wilson lines is proposed. Duality symmetries relating various noncommutative gauge models are being discussed.
We consider a pair of noncommutative lumps in the noncommutative Yang--Mills/M(atrix) model. In the case when the lumps are separated by a finite distance their ``polarisations'' do not belong to orthogonal subspaces of the Hilbert space. In this case the interaction between lumps is nontrivial. We analyse the dynamics arisen due to this interaction in both naive approach of rigid lumps and exactly as described by the underlying gauge model. It appears that the exact description is given in terms of finite matrix models/multidimensional mechanics whose dimensionality depends on the initial conditions.
We consider quantum mechanics on the noncommutative plane in the presence of magnetic field $B$. We show, that the model has two essentially different phases separated by the point $Bθ=c\hbar^2/e$, where $θ$ is a parameter of noncommutativity. In this point the system reduces to exactly-solvable one-dimensional system. When $κ=1-eBθ/c\hbar^2<0$ there is a finite number of states corresponding to the given value of the angular momentum. In another phase, i.e. when $κ>0$ the number of states is infinite. The perturbative spectrum near the critical point $κ=0$ is computed.
We show that the p-dimensional noncommutative Yang--Mills model corresponding to a (p-1)-brane allows solutions which correspond to lower branes. This may be interpreted as the Morita equivalence of noncommutative planes of various dimensions.
We show that the algebra of functions on noncommutative space allows two different representations. One is describing the genuine noncommutative space, while another one can be rewritten in commutative form by a redefinition of generators.
We present some arguments showing spectrum doubling of matrix models in the limit $N\to\infty$ which is connected with fermionic determinant behaviour. The problems are similar to ones encountered in the lattice gauge theories with chiral fermions. One may discuss the ``physical meaning'' of the doubling states or ways to eliminate them. We briefly consider both situations.
Here we construct a map from the algebra of fields in two-dimensional noncommutative of U(1) Yang-Mills fields interacting with Kaluza-Klein scalars to a D-dimensional one, as a solution in the two-dimensional model. This proves the equivalence of noncommutative models in various (even) dimensions. Physically this map describes condensation of D1-branes.
Using a regularisation of the chiral SU(2) Yang-Mills model by an infinite number of Pauli-Villars fields the doubler free gauge invariant lattice model is constructed. Its continuum limit provides the recently proposed mechanism for cancelation of Witten anomaly.