On the projected spectra from a deformed correlated intrinsic state

V. V. Dodonov, E.V. Kurmyshev, Vladimir I. Man’ko

E. J. V. de Passos, A. F. R. de Toledo Piza

Properties of the yrast states of a system of $N$ bosons confined to a one-dimensional ring and interacting via contact forces is examined both variationally and by numerical diagonalizations. The latter allow for obtaining numerical correlated many-body wave functions explicitly. The study of correlation functions involving different yrast states indicates that a quantum phase transition previously detected in the properties of the ground state in the case of attractive two-body interactions is an yrast phenomenon involving the onset of `deformation', in the sense given to this term by Bohr and Mottelson in connection with the description of nuclear spectra, including enhanced transition operators and emergence of a shared intrinsic correlation structure. In this case the moment of inertia of the deformed state is essentially the rigid moment of inertia, `intrinsic' states being essentially degenerate.

Anatol Odzijewicz, Alina Ryżko

Jitendra C. Parikh, DAVID J. ROWE

The importance of ground-state correlations in the spectroscopy of a finite many-particle system, such as the nucleus, is investigated for the model Hamiltonian of Lipkin, Meshkov, and Glick. In particular, we have investigated their effect on the solution of the equations of motion for excitation energies, transition matrix elements, and the correlation energy of the ground state. Methods are studied for calculating the correlations needed to make the necessary corrections to the equations of motion. Also studied is the behavior, with increase of interaction strength, of the phase transition from the spherical to the strongly deformed intrinsic states, in the projected Hartree-Fock scheme.

Luc Lathouwers, E Duemens

The angular momentum projection technique is worked out for systems with an intrinsic asymmetric deformation. These include asymmetric top molecules and triaxial nuclei. A parameterisation of the rotation group is introduced which allows an approximate but analytical evaluation of angular momentum projected matrix elements. Via symmetric orthonormalisation a quantal definition of the moments of inertia is obtained.

J. A. Oke, F. A. Dossa

We establish a rigorous framework for quantum systems with geometric deformations by constructing a strictly self-adjoint deformed momentum operator through the generalized extended momentum operator (GEMO) formalism. Unlike previous approaches relying on boundary-condition hermiticity, our method ensures intrinsic self-adjointness for both linear ($μ(x)=αx$) and quadratic ($μ(x)=αx^{2}$) deformations within a unified non-Hermitian supersymmetric factorization scheme. This yields exact analytical spectra while revealing hidden $\mathfrak{su}(1,1)$ symmetry structures. Crucially, we provide the first complete thermodynamic characterization of such systems by analytically evaluating the partition function via the Euler--Maclaurin approximation. Geometric deformation fundamentally reshapes the density of states $ρ(E)$, producing distinct thermal signatures: a divergent heat capacity peak for linear deformation due to state accumulation near a maximal energy, and a saturation $C/k_{\mathrm{B}}\to 0.6$ (below the Dulong--Petit limit) for quadratic deformation. These results establish geometric deformation as a tunable parameter for engineering quantum thermodynamic responses in curved nanostructures.