Publications


Role of the pair potential for the saturation of generalized Pauli constraints

(2017)

O Legeza, C Schilling

The dependence of the (quasi-)saturation of the generalized Pauli constraints on the pair potential is studied for ground states of few-fermion systems. For this, we consider spinless fermions in one dimension which are harmonically confined and interact by pair potentials of the form |xi−xj|^s with −1≤s≤5. Using the Density Matrix Renormalization Group-approach and large orbital basis sets ensures the convergence on more than ten digits of both the variational energy and the natural occupation numbers. Our results confirm that the conflict between energy minimization and fermionic exchange symmetry results in a quasi-saturation of the generalized Pauli constraints (quasipinning), implying structural simplifications of the fermionic ground state. However, a self-consistent perturbation theory reveals that most of that relevance has to be assigned to Pauli's original exclusion principle, except for the harmonic case, i.e., s=2. This emphasizes the unique nature of the strong, non-trivial quasipinning found recently for the Harmonium model.


Exact matrix product decay modes of a boundary driven cellular automaton

Journal of Physics A: Mathematical and Theoretical 50 (2017)

T Prosen, B Buča

© 2017 IOP Publishing Ltd. We study integrability properties of a reversible deterministic cellular automaton (Rule 54 of (Bobenko et al 1993 Commun. Math. Phys. 158 127)) and present a bulk algebraic relation and its inhomogeneous extension which allow for an explicit construction of Liouvillian decay modes for two distinct families of stochastic boundary driving. The spectrum of the many-body stochastic matrix defining the time propagation is found to separate into sets, which we call orbitals, and the eigenvalues in each orbital are found to obey a distinct set of Bethe-like equations. We construct the decay modes in the first orbital (containing the leading decay mode) in terms of an exact inhomogeneous matrix product ansatz, study the thermodynamic properties of the spectrum and the scaling of its gap, and provide a conjecture for the Bethe-like equations for all the orbitals and their degeneracy.


Charge and spin current statistics of the open Hubbard model with weak coupling to the environment.

Physical review. E 95 (2017) 052141-052141

B Buča, T Prosen

Based on generalization and extension of our previous work [Phys. Rev. Lett. 112, 067201 (2014)PRLTAO0031-900710.1103/PhysRevLett.112.067201] to multiple independent Markovian baths we will compute the charge and spin current statistics of the open Hubbard model with weak system-bath coupling up to next-to-leading order in the coupling parameter. Only the next-to-leading and higher orders depend on the Hubbard interaction parameter. The physical results are related to those for the XXZ model in the analogous setup implying a certain universality, which potentially holds in this class of nonequilibrium models.


Diagonalization of complex symmetric matrices: Generalized Householder reflections, iterative deflation and implicit shifts

COMPUTER PHYSICS COMMUNICATIONS 221 (2017) 304-316

JH Noble, M Lubasch, J Stevens, UD Jentschura


Species-selective confinement of atoms dressed with multiple radiofrequencies

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 50 (2017) ARTN 094002

E Bentine, TL Harte, K Luksch, AJ Barker, J Mur-Petit, B Yuen, CJ Foot


Universal upper bounds on the Bose-Einstein condensate and the Hubbard star

PHYSICAL REVIEW B 96 (2017) ARTN 064502

F Tennie, V Vedral, C Schilling


Reconstructing quantum states from single-party information

Physical Review A: Atomic, Molecular and Optical Physics American Physical Society 96 (2017)

C Schilling, CL Benavides-Riveros, P Vrana

The possible compatibility of density matrices for single-party subsystems is described by linear constraints on their respective spectra. Whenever some of those quantum marginal constraints are saturated, the total quantum state has a specific, simplified structure. We prove that these remarkable global implications of extremal local information are stable; i.e., they hold approximately for spectra close to the boundary of the allowed region. Application of this general result to fermionic quantum systems allows us to characterize natural extensions of the Hartree-Fock ansatz and to quantify their accuracy by resorting to one-particle information, only: The fraction of the correlation energy not recovered by such an ansatz can be estimated from above by a simple geometric quantity in the occupation number picture.


Topological spin models in Rydberg lattices

APPLIED PHYSICS B-LASERS AND OPTICS 123 (2017) ARTN 46

M Kiffner, E O'Brien, D Jaksch


Influence of the fermionic exchange symmetry beyond Pauli's exclusion principle

PHYSICAL REVIEW A 95 (2017) ARTN 022336

F Tennie, V Vedral, C Schilling


Relating correlation measures: The importance of the energy gap

(2017)

CL Benavides-Riveros, NN Lathiotakis, C Schilling, MAL Marques


Relating correlation measures: The importance of the energy gap

Physical Review A American Physical Society 95 (2017) 032507

CL Benavides-Riveros, NN Lathiotakis, C Schilling, M Marques

The concept of correlation is central to all approaches that attempt the description of many-body effects in electronic systems. Multipartite correlation is a quantum information theoretical property that is attributed to quantum states independent of the underlying physics. In quantum chemistry, however, the correlation energy (the energy not seized by the Hartree-Fock ansatz) plays a more prominent role. We show that these two different viewpoints on electron correlation are closely related. The key ingredient turns out to be the energy gap within the symmetry-adapted subspace. We then use a few-site Hubbard model and the stretched H2 to illustrate this connection and to show how the corresponding measures of correlation compare.


Enhancement of superexchange pairing in the periodically driven Hubbard model

PHYSICAL REVIEW B 96 (2017) ARTN 085104

JR Coulthard, SR Clark, S Al-Assam, A Cavalleri, D Jaksch


Terahertz field control of interlayer transport modes in cuprate superconductors

PHYSICAL REVIEW B 96 (2017) ARTN 064526

F Schlawin, ASD Dietrich, M Kiffner, A Cavalleri, D Jaksch


Two-way interconversion of millimeter-wave and optical fields in Rydberg gases

NEW JOURNAL OF PHYSICS 18 (2016) ARTN 093030

M Kiffner, A Feizpour, KT Kaczmarek, D Jaksch, J Nunn


Pinning of fermionic occupation numbers: General concepts and one spatial dimension

PHYSICAL REVIEW A 93 (2016) ARTN 042126

F Tennie, D Ebler, V Vedral, C Schilling


Number-parity effect for confined fermions in one dimension

PHYSICAL REVIEW A 93 (2016) ARTN 021601

C Schilling, R Schilling


Measuring correlations of cold-atom systems using multiple quantum probes

PHYSICAL REVIEW A 94 (2016) ARTN 053634

M Streif, A Buchleitner, D Jaksch, J Mur-Petit


Quantum mechanical calculation of Rydberg-Rydberg autoionization rates

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS 49 (2016) ARTN 204004

M Kiffner, D Ceresoli, W Li, D Jaksch


Natural Extension of Hartree-Fock Through Extremal 1-Fermion Information: Overview and Application to the Lithium Atom

ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS 230 (2016) 703-717

CL Benavides-Riveros, C Schilling


Pinning of fermionic occupation numbers: Higher spatial dimensions and spin

PHYSICAL REVIEW A 94 (2016) ARTN 012120

F Tennie, V Vedral, C Schilling

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