An infinite-dimensional classical integrable system and the Heisenberg and Schrödinger representations

We present an infinite-dimensional classical integrable hamiltonian system on projective Hilbert space. We show that the equations of motion correspond to the Heisenberg ones of quantum mechanics when the hamiltonian operator is compact, and that the formulation of these equations as a classical Lax pair with parameter gives rise naturally to an infinite set of conversation laws. Further, an infinite-dimensional version of Moser's transformation for integrating classical systems is shown to relate the Heisenberg and Schrödinger pictures.     

The Hamiltonian Structure of the Nonlinear Schrödinger Equation and the Asymptotic Stability of its Ground States

In this paper we prove that ground states of the NLS which satisfy the sufficient conditions for orbital stability of M. Weinstein, are also asymptotically stable, for seemingly generic equations. The key issue is to prove that a certain coefficient is non-negative because is a square power. We assume that the NLS has a smooth short range nonlinearity. We assume also the presence of a very short range and smooth linear potential, to avoid translation invariance. The basic idea is to perform a Birkhoff normal form argument on the hamiltonian, as in a paper by Bambusi and Cuccagna on the stability of the 0 solution for NLKG. But in our case, the natural coordinates arising from the linearization are not canonical. So we need also to apply the Darboux Theorem. With some care though, in order not to destroy some nice features of the initial hamiltonian.     

Entropy of Nonstatic Black Hole with the Internal Global Monopole and the Generalized Uncertainty Relation

The new equation of state density is obtained by the utilization of the generalized uncertainty relation. With the help of coordinates and the Wentzel-Kramers-Brillouin approximation, direct calculation of the scalar field entropy of the non-state black hole with an internal global monopole is performed. The entropy obtained from the calculation is proportional to the horizon area. The calculation can be free from convergence if without any cutoff, which is different from the brick-wall method. However, the pertinent result is limited.     

Internal Lifschitz singularities of disordered finite-difference Schrödinger operators

The integrated density of states has C-like singularities, ln|k(E)–k(E _c )|=–|E–E _c |^–v/2 _c (E), with _c >0, a milder function at the edges of the spectral gaps which appear when the distribution function of the potentiald has a sufficiently large gap. The behaviour of _c nearE _c is determined by the local continuity properties ofd near the relevant edge: _c (E)=O(1) ifd has an atom and =O(ln|E–E _c |) if is (absolutely) continuous and power bounded.     

Schrödinger Operators and the Zeros of Their Eigenfunctions

In n-dimensional Euclidean space let us be given an infinitely differentiable real valued function V that is bounded below. We associate with the formal operator that sends a complex valued function ψ into −div(grad ψ) + V ψ a uniquely defined self adjoint operator which we will denote by −Δ + V.     

Growth of Sobolev Norms and Controllability of the Schrödinger Equation

In this paper we obtain a stabilization result for both linear and nonlinear Schrödinger equations under generic assumptions on the potential. Then we consider the Schrödinger equations with a potential which has a random time-dependent amplitude. We show that if the distribution of the amplitude is sufficiently non-degenerate, then any trajectory of the system is almost surely non-bounded in Sobolev spaces.     

Resonances and Their Relations to Spectral Densities and Scattering Cross Sections in the Schrödinger Formulation

The concept of resonances for a two-body single and many channel Schrödinger problem is discussed with respect to the Titchmarsh–Weyl theory. It is argued that the contributions from the entire set of resonances together with the free particle spectral density build the entire spectrum. The implication of this statement on the influence of resonances on a two-body scattering cross section is discussed. It is described how the residues of the S-matrix at a complex resonance energy, i.e. two complex numbers, is used to define its contribution to the cross section. The limitations of the Breit–Wigner approximation is discussed.     

Focusing and multi-focusing solutions of the nonlinear Schrödinger equation

A method of dynamic rescaling of variables is used to investigate numerically the nature of the focusing singularities of the cubic and quintic Schrödinger equations in two and three dimensions and describe their universal properties. The same method is applied to simulate the multi-focusing phenomena produced by simple models of saturating nonlinearities.     

Homogenization of the Schrödinger Equation and Effective Mass Theorems

In this paper we discuss two different models of dependent percolation on the graph ². These models can be thought of as percolation in a random environment. They were inspired by the work of McCoy and Wu [7,8] on the Ising model in a random environment as well as other models of particle systems in a random environment [9, 5, 6, 3]. We show that both models of dependent percolation exhibit phase transitions. This proves a version of stability for percolation on ² and proves a conjecture of Jonasson, Mossel and Peres [4], who proved a similar result on ³.Research supported in part by an NSF postdoctoral fellowshipAcknowledgement I would like to thank David Levin and Yuval Peres for introducing me to the problem. I would also like to thank Yuval Peres and Eric Babson for helpful conversations.     

New results on the moments of the eigenvalues of the Schrödinger Hamiltonian and applications

We show that the moments of order of the eigenvalues of the Schrödinger Hamiltonian inn dimensions can be related to moments of order less than or equal to -1/2 inn+1 dimensions. This makes it possible to improved the bounds on the sum of the eigenvalues in three dimensions and consequently the Lieb-Thiirng bound on the binding energy of matter.     

Fisher information and the complex nature of the Schrödinger wave equation

We show that the minimum Fisher information (MFI) approach to estimating the probability law p(x) on particle position x, over the class of all two-component laws p(x), yields the complex Schrödinger wave equation. Complexity, in particular, traces from an efficiency scenario (demanded by MFI) where the two components of p(x) are so separated that their informations add.     

Thermodynamic Gravity and the Schrödinger Equation

We adopt a formulation of the Mach principle that the rest mass of a particle is a measure of it’s long-range collective interactions with all other particles inside the horizon. As a consequence, all particles in the universe form a ‘gravitationally entangled’ statistical ensemble and one can apply the approach of classical statistical mechanics to it. It is shown that both the Schrödinger equation and the Planck constant can be derived within this Machian model of the universe. The appearance of probabilities, complex wave functions, and quantization conditions is related to the discreetness and finiteness of the Machian ensemble.     

Lagrangian formulation of the Schrödinger equation

We recast the Schrödinger equation in a new Lagrangian formulation. The equation is —i?dψ (x,t)/dt = Lψ (x,t), whereL is the Lagrangian operator. Expressions forL and ford/dt — ⊥ are derived in terms of coordinate and momentum operators.     

On the spectra of Schrödinger operators

We give two formulas for the lowest point in the spectrum of the Schrödinger operatorL=–(d/dt)p(d/dt)+q, where the coefficientsp andq are real-valued, bounded, uniformly continuous functions on the real line. We determine whether or not is an eigenvalue forL in terms of a set of probability measures on the maximal ideal space of theC ^*-algebra generated by the translations ofp andq.Research supported in part by the National Science Foundation under Grant DMS-910496     

Gauge equivalence,supersymmetry and classical solutions of the ospu (1, 1/1) Heisenberg model and the nonlinear Schrödinger equation

An integrable generalization of the continuous classical O(2, 1) pseudospin Heisenberg model to the case of the ospu(1, 1/1) superalgebra is constructed. The gauge equivalence of the constructed model and the related NLSE is established. We indicate a method of generating classical solutions using the global ospu(1, 1/1) supersymmetry. The relationship between solutions of O(2, 1) HM and superpartners of NLSE is obtained.     

Symmetries of the Free Schrödinger Equation

An algorithm is proposed for studying the symmetry properties of equations used in theoretical and mathematical physics. The application of this algorithm to the free Schrödinger equation permits one to establish that, in addition to the known Galilei symmetry, the free Schrödinger equation possesses also relativistic symmetry in some generalized sense. This property of the free Schrödinger equation provides an extension of the equation into the relativistic domain of the free particle motion under study.     

Optical solitons and complexitons of the Schrödinger–Hirota equation

The Schrödinger–Hirota equation governs the propagation of optical solitons in a dispersive optical fiber. In this paper, this equation will be solved by the ansatz method for bright and dark 1-soliton solution. The power law nonlinearity will be assumed. By using the tanh method, some additional solutions will be derived. Finally, the numerical simulations will be given.     

Integrability in the theory of Schrödinger operator and harmonic analysis

The algebraic integrability for the Schrödinger equation in ⁿ and the role of the quantum Calogero-Sutherland problem and root systems in this context are discussed. For the special values of the parameters in the potential the explicit formula for the eigenfunction of the corresponding Sutherland operator is found. As an application the explicit formula for the zonal spherical functions on the symmetric spacesSU _2n ^* /Sp_n (type A II in Cartan notations) is presented.