Infinite Dimensional Analysis, Quantum Probability and Related Topics

We prove that the optimal transportation mapping that takes a Gaussian measure γ on an infinite dimensional space to an equivalent probability measure g·γ satisfies the Monge–Ampère equation provided that log g∈L¹(γ) and g log g∈L¹(γ).

We analyze the two-photon absorption and emission process and characterize the stationary states at zero and positive temperature. We show that entangled stationary states exist only at zero temperature and, at positive temperature, there exists infinitely many commuting invariant states satisfying the detailed balance condition.

Large and moderate deviation principles are proved for the occupation time process of a subcritical branching superprocess with immigration.

In this paper, a sample path large deviation for Fleming–Viot processes corresponding to the small time asymptotics is established. The rate function is identified as the energy functional of paths associated to the Bhattacharya metric, the intrinsic metric of Fleming–Viot processes.

Cabana-Duvillard and lonescu¹¹ have proved that any symmetric probability measure with moments of any order can be obtained as central limit theorem of self-adjoint, weakly independent and symmetrically distributed (in a quantum souse) random variables. Results of this type will be called "universal central limit theorem".

Using Interacting Fock Space (IFS) techniques we extend this result in two directions: (i) we prove that the random variables can be taken to be generalized Gaussian in the sense of Accardi and Bożejko³ and we give a realization of such random variables as sums of creation, annihilation and preservation operators acting on an appropriate IFS; (ii) we extend the above-mentioned result to the nonsymmetric case. The nontrivial difference between the symmetric and the nonsymmetric case is explained at the end of the introduction below.

In Ref. 2 the authors introduced field operators in one-mode type Interacting Fock Spaces whose spectral measures have common symmetric Jacobi recurrence coefficients but differ in the nonsymmetric ones. We show that the convolution of measures arising from addition of such field operators is the universal convolution of Accardi and Bożejko. We also present the associated central limit theorem in a more general form than in Ref. 2 and give it a proof based on the properties of the convolution.

In this paper, we present a new idea to define the δ-function of an observable within the canonical framework of white noise analysis. We introduce a class of observables called δ-composable observables. We then define the δ-function of such an observable as the generalized operator determined uniquely by the spectral density of the observable. Surprisingly, we find that the δ-function of a δ-composable observable is always positive as a generalized operator. Finally, we show an example of a δ-composable observable and examine properties of its δ-function.

We define a deformation of free creations (and annihilations), given by operators on the full Fock space, acting nontrivially only between the vacuum subspace ℂΩ and the twofold tensor product . Then we study the distribution of the deformed free gaussian operators, with the deformation containing also a real parameter d. The recurrence formula for moments is shown, and the Cauchy transform of the distribution measure is computed. This yields the description of the measure: absolutely continuous part and the atomic part. The existence of atoms depends on the parameter d. The special case d =1 is studied with all details, with the formula for moments is given as values of the hypergeometric series. Finally we show the formula for computing the mixed moments of the deformed operators.