Valentin Kasper
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View article: Nonperturbative signatures of fractons in the twisted multiflavor Schwinger Model
Nonperturbative signatures of fractons in the twisted multiflavor Schwinger Model Open
Gauge-field configurations with nontrivial topology have profound consequences for the physics of Abelian and non-Abelian gauge theories. Over time, arguments have been gathering for the existence of gauge-field configurations with fractio…
View article: Chirped pulse control over the melting of superconductors
Chirped pulse control over the melting of superconductors Open
Strong field terahertz pulses are increasingly used to excite and control quantum materials at the ultrafast timescale. They have found widespread application by enabling direct addressing of the superconducting gap or Josephson resonances…
View article: Qudit-native measurement protocol for dynamical correlations using Hadamard tests
Qudit-native measurement protocol for dynamical correlations using Hadamard tests Open
Dynamical correlations reveal important out-of-equilibrium properties of the underlying quantum many-body system, yet they are notoriously difficult to measure in experiments. While measurement protocols for dynamical correlations based on…
View article: Author Correction: Engineering holography with stabilizer graph codes
Author Correction: Engineering holography with stabilizer graph codes Open
The discovery of holographic codes established a surprising connection between quantum error correction and the anti-de Sitter-conformal field theory correspondence.Recent technological progress in artificial quantum systems renders the ex…
View article: Engineering holography with stabilizer graph codes
Engineering holography with stabilizer graph codes Open
The discovery of holographic codes established a surprising connection between quantum error correction and the anti-de Sitter-conformal field theory correspondence. Recent technological progress in artificial quantum systems renders the e…
View article: Nonperturbative signatures of fractons in the twisted multiflavor Schwinger Model
Nonperturbative signatures of fractons in the twisted multiflavor Schwinger Model Open
Gauge-field configurations with nontrivial topology have profound consequences for the physics of Abelian and non-Abelian gauge theories. Over time, arguments have been gathering for the existence of gauge-field configurations with fractio…
View article: Chirped pulse control over the melting of superconductors
Chirped pulse control over the melting of superconductors Open
Strong field terahertz pulses are increasingly used to excite and control quantum materials at the ultrafast timescale. They have found widespread application by enabling direct addressing of the superconducting gap or Josephson resonances…
View article: Variational quantum simulation of U(1) lattice gauge theories with qudit systems
Variational quantum simulation of U(1) lattice gauge theories with qudit systems Open
Lattice gauge theories are fundamental to various fields, including particle physics, condensed matter, and quantum information theory. Recent progress in the control of quantum systems allows for studying Abelian lattice gauge theories in…
View article: Variational quantum simulation of U(1) lattice gauge theories with qudit systems
Variational quantum simulation of U(1) lattice gauge theories with qudit systems Open
Lattice gauge theories are fundamental to various fields, including particle physics, condensed matter, and quantum information theory. Recent progress in the control of quantum systems allows for studying Abelian lattice gauge theories in…
View article: Topological Bogoliubov quasiparticles from Bose-Einstein condensate in a flat band system
Topological Bogoliubov quasiparticles from Bose-Einstein condensate in a flat band system Open
For bosons with flat energy dispersion, condensation can occur in different symmetry sectors. Here, we consider bosons in a Kagome lattice with $π$-flux hopping, which in the presence of mean-field interactions exhibit degenerate condensat…
View article: Engineering holography with stabilizer graph codes
Engineering holography with stabilizer graph codes Open
The discovery of holographic codes established a surprising connection between quantum error correction and the anti-de Sitter-conformal field theory correspondence. Recent technological progress in artificial quantum systems renders the e…
View article: Engineering a U(1) lattice gauge theory in classical electric circuits
Engineering a U(1) lattice gauge theory in classical electric circuits Open
Lattice gauge theories are fundamental to such distinct fields as particle\nphysics, condensed matter, and quantum information science. Their local\nsymmetries enforce the charge conservation observed in the laws of physics.\nImpressive ex…
View article: Non-equilibrium dynamics of fluctuations in an ultra-cold atomic mixture
Non-equilibrium dynamics of fluctuations in an ultra-cold atomic mixture Open
We investigate an ultra-cold mixture of Bose gases interacting via spin-changing collisions by studying the dynamics of spin fluctuations. The experimental implementation employs $^{23}$Na and $^{7}$Li atoms, which are prepared out of equi…
View article: Quantum approximate optimization algorithm for qudit systems
Quantum approximate optimization algorithm for qudit systems Open
A frequent starting point of quantum computation platforms are two-state quantum systems, i.e., qubits. However, in the context of integer optimization problems, relevant to scheduling optimization and operations research, it is often more…
View article: Cold atoms meet lattice gauge theory
Cold atoms meet lattice gauge theory Open
The central idea of this review is to consider quantum field theory models relevant for particle physics and replace the fermionic matter in these models by a bosonic one. This is mostly motivated by the fact that bosons are more ‘accessib…
View article: Storage properties of a quantum perceptron
Storage properties of a quantum perceptron Open
Driven by growing computational power and algorithmic developments, machine learning methods have become valuable tools for analyzing vast amounts of data. Simultaneously, the fast technological progress of quantum information processing s…
View article: Universal quantum computation and quantum error correction with ultracold atomic mixtures
Universal quantum computation and quantum error correction with ultracold atomic mixtures Open
Quantum information platforms made great progress in the control of many-body entanglement and the implementation of quantum error correction, but it remains a challenge to realize both in the same setup. Here, we propose a mixture of two …
View article: Preparation of the 1/2 Laughlin state with atoms in a rotating trap
Preparation of the 1/2 Laughlin state with atoms in a rotating trap Open
Made available in DSpace on 2022-04-29T08:30:11Z (GMT). No. of bitstreams: 0\n Previous issue date: 2021-06-01
View article: Storage capacity and learning capability of quantum neural networks
Storage capacity and learning capability of quantum neural networks Open
We study the storage capacity of quantum neural networks (QNNs), described by completely positive trace preserving (CPTP) maps acting on an N -dimensional Hilbert space. We demonstrate that attractor QNNs can store in a non-trivial manner …
View article: Non-Abelian gauge invariance from dynamical decoupling
Non-Abelian gauge invariance from dynamical decoupling Open
Lattice gauge theories are fundamental to such distinct fields as particle physics, condensed matter or quantum information theory. The recent progress in the control of artificial quantum systems already allows for studying Abelian lattic…
View article: Fate of Lattice Gauge Theories Under Decoherence
Fate of Lattice Gauge Theories Under Decoherence Open
A major test of the capabilities of modern quantum simulators and NISQ devices is the reliable realization of gauge theories, which constitute a gold standard of implementational efficacy. In addition to unavoidable unitary errors, realist…
View article: Simulating a quantum commensurate-incommensurate phase transition using two Raman-coupled one-dimensional condensates
Simulating a quantum commensurate-incommensurate phase transition using two Raman-coupled one-dimensional condensates Open
We study a transition between a homogeneous and an inhomogeneous phase in a system of one-dimensional, Raman tunnel-coupled Bose gases. The homogeneous phase shows a flat density and phase profile, whereas the inhomogeneous ground state is…
View article: Quantum quench of the Sachdev-Ye-Kitaev model
Quantum quench of the Sachdev-Ye-Kitaev model Open
We describe the nonequilibrium quench dynamics of the Sachdev-Ye-Kitaev models of fermions with random all-to-all interactions. These provide tractable models of the dynamics of quantum systems without quasiparticle excitations. The Kadano…
View article: Inflationary preheating dynamics with two-species condensates
Inflationary preheating dynamics with two-species condensates Open
We discuss the amplification of loop corrections in quantum many-body systems through dynamical instabilities. As an example, we investigate both analytically and numerically a two-component ultracold atom system in one spatial dimension. …
View article: Implementing quantum electrodynamics with ultracold atomic systems
Implementing quantum electrodynamics with ultracold atomic systems Open
We discuss the experimental engineering of model systems for the description of QED in one spatial dimension via a mixture of bosonic $^{23}$Na and fermionic $^6$Li atoms. The local gauge symmetry is realized in an optical superlattice, us…
View article: Schwinger pair production with ultracold atoms
Schwinger pair production with ultracold atoms Open
We consider a system of ultracold atoms in an optical lattice as a quantum simulator for electron-positron pair production in quantum electrodynamics (QED). For a setup in one spatial dimension, we investigate the nonequilibrium phenomenon…
View article: Phase Space Approach to Dynamics of Interacting Fermions
Phase Space Approach to Dynamics of Interacting Fermions Open
Understanding the behavior of interacting fermions is of fundamental interest in many fields ranging from condensed matter to high energy physics. Developing numerically efficient and accurate simulation methods is an indispensable part of…
View article: Lattice Gauge Theory and Cold Atoms Out of Equilibrium
Lattice Gauge Theory and Cold Atoms Out of Equilibrium Open
In this thesis we theoretically investigate the quantum simulation of lattice gauge theories for cold atom experiments. We give an explicit proposal to study a (1+1) -
\ndimensional U(1) lattice gauge theory. Starting with a bosonic and a …