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A nonlinear electromagnetic scattering problem is studied in the presence of bound states in the radiation continuum. It is shown that the solution is not analytic in the nonlinear susceptibility and the conventional perturbation theory…

Mathematical Physics · Physics 2012-03-12 Friends Remy Ndangali , Sergei V. Shabanov

A summary is presented of the properties of the coefficient matrices formed by expanding the two-body reduced density matrix in a complete set of two-electron wave functions. Calculating the relationship between the many electron wave…

Quantum Physics · Physics 2022-03-02 Nicholas Cox

In this paper, we propose second-order sufficient optimality conditions for a very general nonconvex constrained optimization problem, which covers many prominent mathematical programs.Unlike the existing results in the literature, our…

Optimization and Control · Mathematics 2022-11-24 Matus Benko , Helmut Gfrerer , Jane Ye , Jin Zhang , Jinchuan Zhou

The paper is devoted to deriving novel second-order necessary and sufficient optimality conditions for local minimizers in rather general classes of nonsmooth unconstrained and constrained optimization problems in finite-dimensional spaces.…

Optimization and Control · Mathematics 2025-01-07 Pham Duy Khanh , Vu Vinh Huy Khoa , Boris S. Mordukhovich , Vo Thanh Phat

The transient quantum statistical properties of the atoms and molecules in an atom-molecule BEC system are investigated by obtaining a third-order perturbative solution of the Heisenberg's equations of motion corresponding to the…

Quantum Physics · Physics 2014-07-08 Sandip Kumar Giri , Kishore Thapliyal , Biswajit Sen , Anirban Pathak

Variational calculation of the ground state energy and its properties using the second-order reduced density matrix (2-RDM) is a promising approach for quantum chemistry. A major obstacle with this approach is that the $N$-representability…

Chemical Physics · Physics 2011-08-30 Maho Nakata

The second-order reduced density matrix method (the RDM method) has performed well in determining energies and properties of atomic and molecular systems, achieving coupled-cluster singles and doubles with perturbative triples (CC SD(T))…

Strongly Correlated Electrons · Physics 2012-07-23 James S. M. Anderson , Maho Nakata , Ryo Igarashi , Katsuki Fujisawa , Makoto Yamashita

The isoelectronic series of Be, Ne and Si are investigated using a variational determination of the second-order density matrix. A semidefinite program was developed that exploits all rotational and spin symmetries in the atomic system. We…

Strongly Correlated Electrons · Physics 2009-09-14 Brecht Verstichel , Helen van Aggelen , Dimitri Van Neck , Paul W. Ayers , Patrick Bultinck

Many quantum algorithms, including recently proposed hybrid classical/quantum algorithms, make use of restricted tomography of the quantum state that measures the reduced density matrices, or marginals, of the full state. The most…

Quantum Physics · Physics 2018-05-16 Nicholas C. Rubin , Ryan Babbush , Jarrod McClean

In intensity-modulated radiation therapy, optimal intensity distributions of incoming beams are decomposed into linear combinations of leaf openings of a multileaf collimator (segments). In order to avoid inefficient dose delivery, the…

Medical Physics · Physics 2010-09-29 Antje Kiesel , Tobias Gauer

In this paper, we prove the existence of minimizers of a class of multi-constrained variational problems. We consider systems involving a nonlinearity that does not satisfy compactness, monotonicity, neither symmetry properties. Our…

Analysis of PDEs · Mathematics 2013-10-10 Hichem Hajaiej , Peter A. Markowich , Saber Trabelsi

In bidisperse particle mixtures varying in size or density alone, large particles rise (driven by percolation) and heavy particles sink (driven by buoyancy). When the two particle species differ from each other in both size and density, the…

Soft Condensed Matter · Physics 2021-06-09 Yifei Duan , Paul B. Umbanhowar , Richard M. Lueptow

The electron energy and density matrices in molecular systems are convex in respect of the number of particles. So that, the chemical descriptors based on their derivatives present the hamper of discontinuities for isolated systems and…

Chemical Physics · Physics 2015-06-10 Roberto C. Bochicchio

This paper studies the problem of reconstructing binary matrices that are only accessible through few evaluations of their discrete X-rays. Such question is prominently motivated by the demand in material science for developing a tool for…

Combinatorics · Mathematics 2007-05-23 Alberto Del Lungo , Andrea Frosini , Maurice Nivat , Laurent Vuillon

Many-body wavefunctions usually lie in high-dimensional Hilbert spaces. However, physically relevant states, i.e, the eigenstates of the Schr\"odinger equation are rare. For many-body systems involving only pairwise interactions, these…

Quantum Physics · Physics 2023-01-05 Chaoming Song

Atomic arrays can exhibit collective light emission when the transition wavelength exceeds their lattice spacing. Subradiant states take advantage of this phenomenon to drastically reduce their overall decay rate, allowing for long-lived…

Quantum Physics · Physics 2024-01-29 Nik O. Gjonbalaj , Stefan Ostermann , Susanne F. Yelin

We analyze a macroscopic model with a maximal density constraint which describes short range repulsion in biological systems. This system aims at modeling finite-size particles which cannot overlap and repel each other when they are too…

Mathematical Physics · Physics 2014-04-08 Pierre Degond , Laurent Navoret , Richard Bon , David Sanchez

We establish necessary and sufficient conditions for the N-representability of the universal one-electron reduced density matrix functional. Functionals satisfying these conditions are guaranteed to yield variational upper bounds on the…

Quantum Physics · Physics 2026-04-08 Jannis Erhard , Paul W. Ayers

We discuss existence of mixed state of multicomponent system with given spectrum and given reduced density matrices. We give a complete solution of the problem in terms of linear inequalities on the spectra, accompanied with extensive…

Quantum Physics · Physics 2007-05-23 Alexander Klyachko

Cell sorting, whereby a heterogeneous cell mixture segregates and forms distinct homogeneous tissues, is one of the main collective cell behaviors at work during development. Although differences in interfacial energies are recognized to be…

Soft Condensed Matter · Physics 2022-07-15 Marc Durand