Quantum optics theoryhttp://hdl.handle.net/2117/238582024-03-29T09:02:11Z2024-03-29T09:02:11ZNeutron Ionization of Helium near the Neutron-Alpha Particle Collision ResonancePindzola, M. S.Colgan, J.Ciappina, M. F.http://hdl.handle.net/2117/3683422022-06-19T15:02:04Z2022-06-13T10:24:25ZNeutron Ionization of Helium near the Neutron-Alpha Particle Collision Resonance
Pindzola, M. S.; Colgan, J.; Ciappina, M. F.
Neutron-impact single and double ionization cross sections of the He atom are calculated near the neutron-alpha particle collision resonance. Calculations using the time-dependent close-coupling method for total and differential cross sections are made at 8 incident neutron energies ranging from 250 to 2000 keV. At the resonance energy peak the double ionization cross sections unexpectedly become larger than the single ionization cross sections. This finding appears to be related to the high velocity of the recoiling alpha particle, which makes it unlikely that the atomic electrons can recombine with the alpha particle nucleus, enhancing the double ionization cross section.
2022-06-13T10:24:25ZPindzola, M. S.Colgan, J.Ciappina, M. F.Neutron-impact single and double ionization cross sections of the He atom are calculated near the neutron-alpha particle collision resonance. Calculations using the time-dependent close-coupling method for total and differential cross sections are made at 8 incident neutron energies ranging from 250 to 2000 keV. At the resonance energy peak the double ionization cross sections unexpectedly become larger than the single ionization cross sections. This finding appears to be related to the high velocity of the recoiling alpha particle, which makes it unlikely that the atomic electrons can recombine with the alpha particle nucleus, enhancing the double ionization cross section.A systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generationWoźniak, AleksanderLesiuk, MichalPrzybytek, MichalEfimov, Dmitry K.Prauzner-Bechcicki, Jakub S.Mandrysz, MichalCiappina, MarceloPisanty, EmilioZakrzewski, JakubLewenstein, MaciejMoszyński, Roberthttp://hdl.handle.net/2117/3634242022-03-06T16:50:01Z2022-03-04T10:12:19ZA systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generation
Woźniak, Aleksander; Lesiuk, Michal; Przybytek, Michal; Efimov, Dmitry K.; Prauzner-Bechcicki, Jakub S.; Mandrysz, Michal; Ciappina, Marcelo; Pisanty, Emilio; Zakrzewski, Jakub; Lewenstein, Maciej; Moszyński, Robert
A precise understanding of mechanisms governing the dynamics of electrons in atoms and molecules subjected to intense laser fields has a key importance for the description of attosecond processes such as the high-harmonic generation and ionization. From the theoretical point of view, this is still a challenging task, as new approaches to solve the time-dependent Schrödinger equation with both good accuracy and efficiency are still emerging. Until recently, the purely numerical methods of real-time propagation of the wavefunction using finite grids have been frequently and successfully used to capture the electron dynamics in small one- or two-electron systems. However, as the main focus of attoscience shifts toward many-electron systems, such techniques are no longer effective and need to be replaced by more approximate but computationally efficient ones. In this paper, we explore the increasingly popular method of expanding the wavefunction of the examined system into a linear combination of atomic orbitals and present a novel systematic scheme for constructing an optimal Gaussian basis set suitable for the description of excited and continuum atomic or molecular states. We analyze the performance of the proposed basis sets by carrying out a series of time-dependent configuration interaction calculations for the hydrogen atom in fields of intensity varying from 5 × 1013 W/cm2 to 5 × 1014 W/cm2. We also compare the results with the data obtained using Gaussian basis sets proposed previously by other authors.
ACKNOWLEDGMENTS
2022-03-04T10:12:19ZWoźniak, AleksanderLesiuk, MichalPrzybytek, MichalEfimov, Dmitry K.Prauzner-Bechcicki, Jakub S.Mandrysz, MichalCiappina, MarceloPisanty, EmilioZakrzewski, JakubLewenstein, MaciejMoszyński, RobertA precise understanding of mechanisms governing the dynamics of electrons in atoms and molecules subjected to intense laser fields has a key importance for the description of attosecond processes such as the high-harmonic generation and ionization. From the theoretical point of view, this is still a challenging task, as new approaches to solve the time-dependent Schrödinger equation with both good accuracy and efficiency are still emerging. Until recently, the purely numerical methods of real-time propagation of the wavefunction using finite grids have been frequently and successfully used to capture the electron dynamics in small one- or two-electron systems. However, as the main focus of attoscience shifts toward many-electron systems, such techniques are no longer effective and need to be replaced by more approximate but computationally efficient ones. In this paper, we explore the increasingly popular method of expanding the wavefunction of the examined system into a linear combination of atomic orbitals and present a novel systematic scheme for constructing an optimal Gaussian basis set suitable for the description of excited and continuum atomic or molecular states. We analyze the performance of the proposed basis sets by carrying out a series of time-dependent configuration interaction calculations for the hydrogen atom in fields of intensity varying from 5 × 1013 W/cm2 to 5 × 1014 W/cm2. We also compare the results with the data obtained using Gaussian basis sets proposed previously by other authors.
ACKNOWLEDGMENTSGeneration of optical Schrödinger cat states in intense laser-matter interactionsLewenstein, MaciejCiappina, M. F.Pisanty, E.Rivera-Dean, J.Stammer, P.Lamprou, Th.Tzallas, P.http://hdl.handle.net/2117/3634212022-07-15T11:03:12Z2022-03-04T09:52:31ZGeneration of optical Schrödinger cat states in intense laser-matter interactions
Lewenstein, Maciej; Ciappina, M. F.; Pisanty, E.; Rivera-Dean, J.; Stammer, P.; Lamprou, Th.; Tzallas, P.
The physics of intense laser–matter interactions1,2 is described by treating the light pulses classically, anticipating no need to access optical measurements beyond the classical limit. However, the quantum nature of the electromagnetic fields is always present3. Here we demonstrate that intense laser–atom interactions may lead to the generation of highly non-classical light states. This was achieved by using the process of high-harmonic generation in atoms4,5, in which the photons of a driving laser pulse of infrared frequency are upconverted into photons of higher frequencies in the extreme ultraviolet spectral range. The quantum state of the fundamental mode after the interaction, when conditioned on the high-harmonic generation, is a so-called Schrödinger cat state, which corresponds to a superposition of two distinct coherent states: the initial state of the laser and the coherent state reduced in amplitude that results from the interaction with atoms. The results open the path for investigations towards the control of the non-classical states, exploiting conditioning approaches on physical processes relevant to high-harmonic generation.
2022-03-04T09:52:31ZLewenstein, MaciejCiappina, M. F.Pisanty, E.Rivera-Dean, J.Stammer, P.Lamprou, Th.Tzallas, P.The physics of intense laser–matter interactions1,2 is described by treating the light pulses classically, anticipating no need to access optical measurements beyond the classical limit. However, the quantum nature of the electromagnetic fields is always present3. Here we demonstrate that intense laser–atom interactions may lead to the generation of highly non-classical light states. This was achieved by using the process of high-harmonic generation in atoms4,5, in which the photons of a driving laser pulse of infrared frequency are upconverted into photons of higher frequencies in the extreme ultraviolet spectral range. The quantum state of the fundamental mode after the interaction, when conditioned on the high-harmonic generation, is a so-called Schrödinger cat state, which corresponds to a superposition of two distinct coherent states: the initial state of the laser and the coherent state reduced in amplitude that results from the interaction with atoms. The results open the path for investigations towards the control of the non-classical states, exploiting conditioning approaches on physical processes relevant to high-harmonic generation.The imaginary part of the high-harmonic cutoffPisanty, EmilioCiappina, Marcelo F.Lewenstein, Maciejhttp://hdl.handle.net/2117/3282192022-05-17T17:12:31Z2020-08-25T15:06:42ZThe imaginary part of the high-harmonic cutoff
Pisanty, Emilio; Ciappina, Marcelo F.; Lewenstein, Maciej
High-harmonic generation the emission of high-frequency radiation by the ionization and
subsequent recombination of an atomic electron driven by a strong laser eld is widely understood
using a quasiclassical trajectory formalism, derived from a saddle-point approximation, where
each saddle corresponds to a complex-valued trajectory whose recombination contributes to the
harmonic emission. However, the classi cation of these saddle points into individual quantum
orbits remains a high-friction part of the formalism. Here we present a scheme to classify these
trajectories, based on a natural identi cation of the (complex) time that corresponds to the
harmonic cuto . This identi cation also provides a natural complex value for the cuto energy,
whose imaginary part controls the strength of quantum-path interference between the quantum
orbits that meet at the cuto . Our construction gives an e cient method to evaluate the location
and brightness of the cuto for a wide class of driver waveforms by solving a single saddle-point
equation. It also allows us to explore the intricate topologies of the Riemann surfaces formed by
the quantum orbits induced by nontrivial waveforms.
2020-08-25T15:06:42ZPisanty, EmilioCiappina, Marcelo F.Lewenstein, MaciejHigh-harmonic generation the emission of high-frequency radiation by the ionization and
subsequent recombination of an atomic electron driven by a strong laser eld is widely understood
using a quasiclassical trajectory formalism, derived from a saddle-point approximation, where
each saddle corresponds to a complex-valued trajectory whose recombination contributes to the
harmonic emission. However, the classi cation of these saddle points into individual quantum
orbits remains a high-friction part of the formalism. Here we present a scheme to classify these
trajectories, based on a natural identi cation of the (complex) time that corresponds to the
harmonic cuto . This identi cation also provides a natural complex value for the cuto energy,
whose imaginary part controls the strength of quantum-path interference between the quantum
orbits that meet at the cuto . Our construction gives an e cient method to evaluate the location
and brightness of the cuto for a wide class of driver waveforms by solving a single saddle-point
equation. It also allows us to explore the intricate topologies of the Riemann surfaces formed by
the quantum orbits induced by nontrivial waveforms.Symphony on strong field approximationAmini, KasraBiegert, JensCalegari, FrancescaChacón, AlexisCiappina, Marcelo F.Dauphin, AlexandreEfimov, Dmitry K.Figueira de Morisson Faria, CarlaGiergiel, KrzysztofGniewek, PiotrLandsman, Alexandra S.Lesiuk, MichałMandrysz, MichałMaxwell, Andrew S.Moszynski, RobertOrtmann, LisaPérez-Hernández, Jose AntonioPicón, AntonioPisanty, EmilioPrauzner-Bechcicki, JakubSacha, KrzysztofSuárez, NoslenZaïr, AmelleZakrzewski, JakubLewenstein, Maciejhttp://hdl.handle.net/2117/1709992022-05-17T11:16:13Z2019-10-28T17:00:31ZSymphony on strong field approximation
Amini, Kasra; Biegert, Jens; Calegari, Francesca; Chacón, Alexis; Ciappina, Marcelo F.; Dauphin, Alexandre; Efimov, Dmitry K.; Figueira de Morisson Faria, Carla; Giergiel, Krzysztof; Gniewek, Piotr; Landsman, Alexandra S.; Lesiuk, Michał; Mandrysz, Michał; Maxwell, Andrew S.; Moszynski, Robert; Ortmann, Lisa; Pérez-Hernández, Jose Antonio; Picón, Antonio; Pisanty, Emilio; Prauzner-Bechcicki, Jakub; Sacha, Krzysztof; Suárez, Noslen; Zaïr, Amelle; Zakrzewski, Jakub; Lewenstein, Maciej
This paper has been prepared by the Symphony collaboration (University of Warsaw,
Uniwersytet Jagielloński, DESY/CNR and ICFO) on the occasion of the 25th anniversary of
the ‘simple man’s models’ which underlie most of the phenomena that occur when intense
ultrashort laser pulses interact with matter. The phenomena in question include high-harmonic
generation (HHG), above-threshold ionization (ATI), and non-sequential multielectron
ionization (NSMI). ‘Simple man’s models’ provide both an intuitive basis for understanding
the numerical solutions of the time-dependent Schrödinger equation and the motivation for the
powerful analytic approximations generally known as the strong field approximation (SFA).
In this paper we first review the SFA in the form developed by us in the last 25 years. In this approach the SFA is a method to solve the TDSE, in which the non-perturbative interactions
are described by including continuum–continuum interactions in a systematic perturbation-like
theory. In this review we focus on recent applications of the SFA to HHG, ATI and NSMI from
multi-electron atoms and from multi-atom molecules. The main novel part of the presented
theory concerns generalizations of the SFA to: (i) time-dependent treatment of two-electron
atoms, allowing for studies of an interplay between electron impact ionization and resonant
excitation with subsequent ionization; (ii) time-dependent treatment in the single active
electron approximation of ‘large’ molecules and targets which are themselves undergoing
dynamics during the HHG or ATI processes. In particular, we formulate the general expressions
for the case of arbitrary molecules, combining input from quantum chemistry and quantum
dynamics. We formulate also theory of time-dependent separable molecular potentials to model
analytically the dynamics of realistic electronic wave packets for molecules in strong laser
fields.
2019-10-28T17:00:31ZAmini, KasraBiegert, JensCalegari, FrancescaChacón, AlexisCiappina, Marcelo F.Dauphin, AlexandreEfimov, Dmitry K.Figueira de Morisson Faria, CarlaGiergiel, KrzysztofGniewek, PiotrLandsman, Alexandra S.Lesiuk, MichałMandrysz, MichałMaxwell, Andrew S.Moszynski, RobertOrtmann, LisaPérez-Hernández, Jose AntonioPicón, AntonioPisanty, EmilioPrauzner-Bechcicki, JakubSacha, KrzysztofSuárez, NoslenZaïr, AmelleZakrzewski, JakubLewenstein, MaciejThis paper has been prepared by the Symphony collaboration (University of Warsaw,
Uniwersytet Jagielloński, DESY/CNR and ICFO) on the occasion of the 25th anniversary of
the ‘simple man’s models’ which underlie most of the phenomena that occur when intense
ultrashort laser pulses interact with matter. The phenomena in question include high-harmonic
generation (HHG), above-threshold ionization (ATI), and non-sequential multielectron
ionization (NSMI). ‘Simple man’s models’ provide both an intuitive basis for understanding
the numerical solutions of the time-dependent Schrödinger equation and the motivation for the
powerful analytic approximations generally known as the strong field approximation (SFA).
In this paper we first review the SFA in the form developed by us in the last 25 years. In this approach the SFA is a method to solve the TDSE, in which the non-perturbative interactions
are described by including continuum–continuum interactions in a systematic perturbation-like
theory. In this review we focus on recent applications of the SFA to HHG, ATI and NSMI from
multi-electron atoms and from multi-atom molecules. The main novel part of the presented
theory concerns generalizations of the SFA to: (i) time-dependent treatment of two-electron
atoms, allowing for studies of an interplay between electron impact ionization and resonant
excitation with subsequent ionization; (ii) time-dependent treatment in the single active
electron approximation of ‘large’ molecules and targets which are themselves undergoing
dynamics during the HHG or ATI processes. In particular, we formulate the general expressions
for the case of arbitrary molecules, combining input from quantum chemistry and quantum
dynamics. We formulate also theory of time-dependent separable molecular potentials to model
analytically the dynamics of realistic electronic wave packets for molecules in strong laser
fields.Knotting fractional-order knots with the polarization state of lightPisanty, EmilioMachado, Gerard J.Vicuña-Hernández, VerónicaPicón, AntonioCeli, AlessioPérez Torres, JuanLewenstein, Maciejhttp://hdl.handle.net/2117/1668612022-05-17T10:25:49Z2019-07-25T10:32:01ZKnotting fractional-order knots with the polarization state of light
Pisanty, Emilio; Machado, Gerard J.; Vicuña-Hernández, Verónica; Picón, Antonio; Celi, Alessio; Pérez Torres, Juan; Lewenstein, Maciej
The fundamental polarization singularities of monochromatic light are normally associated with invariance under coordinated rotations: symmetry operations that rotate the spatial dependence of an electromagnetic field by an angle and its polarization by a multiple of that angle. These symmetries are generated by mixed angular momenta of the form J_γ = L + γ S, and they generally induce Möbius-strip topologies, with the coordination parameter restricted to integer and half-integer values. In this work we construct beams of light that are invariant under coordinated rotations for arbitrary rational γ, by exploiting the higher internal symmetry of ‘bicircular’ superpositions of counter-rotating circularly polarized beams at different frequencies. We show that these beams have the topology of a torus knot, which reflects the subgroup generated by the torus-knot angular momentum J_γ, and we characterize the resulting optical polarization singularity using third-and higher-order field moment tensors, which we experimentally observe using nonlinear polarization tomography.
2019-07-25T10:32:01ZPisanty, EmilioMachado, Gerard J.Vicuña-Hernández, VerónicaPicón, AntonioCeli, AlessioPérez Torres, JuanLewenstein, MaciejThe fundamental polarization singularities of monochromatic light are normally associated with invariance under coordinated rotations: symmetry operations that rotate the spatial dependence of an electromagnetic field by an angle and its polarization by a multiple of that angle. These symmetries are generated by mixed angular momenta of the form J_γ = L + γ S, and they generally induce Möbius-strip topologies, with the coordination parameter restricted to integer and half-integer values. In this work we construct beams of light that are invariant under coordinated rotations for arbitrary rational γ, by exploiting the higher internal symmetry of ‘bicircular’ superpositions of counter-rotating circularly polarized beams at different frequencies. We show that these beams have the topology of a torus knot, which reflects the subgroup generated by the torus-knot angular momentum J_γ, and we characterize the resulting optical polarization singularity using third-and higher-order field moment tensors, which we experimentally observe using nonlinear polarization tomography.Terahertz field control of in-plane orbital order in La0.5Sr1.5MnO4Miller, Timothy A.Chhajlany, Ravindra W.Tagliacozzo, LucaGreen, BertramKovalev, SergeyPrabhakaran, DharmalingamLewenstein, MaciejGensch, MichaelWall, Simonhttp://hdl.handle.net/2117/791402020-07-22T18:04:20Z2015-11-12T14:43:09ZTerahertz field control of in-plane orbital order in La0.5Sr1.5MnO4
Miller, Timothy A.; Chhajlany, Ravindra W.; Tagliacozzo, Luca; Green, Bertram; Kovalev, Sergey; Prabhakaran, Dharmalingam; Lewenstein, Maciej; Gensch, Michael; Wall, Simon
In-plane anisotropic ground states are ubiquitous in correlated solids such as pnictides, cuprates and manganites. They can arise from doping Mott insulators and compete with phases such as superconductivity; however, their origins are debated. Strong coupling between lattice, charge, orbital and spin degrees of freedom results in simultaneous ordering of multiple parameters, masking the mechanism that drives the transition. Here we demonstrate that the orbital domains in a manganite can be oriented by the polarization of a pulsed THz light field. Through the application of a Hubbard model, we show that domain control can be achieved by enhancing the local Coulomb interactions, which drive domain reorientation. Our results highlight the key role played by the Coulomb interaction in the control and manipulation of orbital order in the manganites and demonstrate a new way to use THz to understand and manipulate anisotropic phases in a potentially broad range of correlated materials.
2015-11-12T14:43:09ZMiller, Timothy A.Chhajlany, Ravindra W.Tagliacozzo, LucaGreen, BertramKovalev, SergeyPrabhakaran, DharmalingamLewenstein, MaciejGensch, MichaelWall, SimonIn-plane anisotropic ground states are ubiquitous in correlated solids such as pnictides, cuprates and manganites. They can arise from doping Mott insulators and compete with phases such as superconductivity; however, their origins are debated. Strong coupling between lattice, charge, orbital and spin degrees of freedom results in simultaneous ordering of multiple parameters, masking the mechanism that drives the transition. Here we demonstrate that the orbital domains in a manganite can be oriented by the polarization of a pulsed THz light field. Through the application of a Hubbard model, we show that domain control can be achieved by enhancing the local Coulomb interactions, which drive domain reorientation. Our results highlight the key role played by the Coulomb interaction in the control and manipulation of orbital order in the manganites and demonstrate a new way to use THz to understand and manipulate anisotropic phases in a potentially broad range of correlated materials.Inequivalence of entanglement, steering, and Bell nonlocality for general measurementsQuintino, Marco TulioVértesi, TamasCavalcanti, DanielAugusiak, RemigiuszDemianowicz, MaciejAcín dal Maschio, AntonioBrunner, Nicolashttp://hdl.handle.net/2117/790102022-12-21T08:10:49Z2015-11-11T12:06:43ZInequivalence of entanglement, steering, and Bell nonlocality for general measurements
Quintino, Marco Tulio; Vértesi, Tamas; Cavalcanti, Daniel; Augusiak, Remigiusz; Demianowicz, Maciej; Acín dal Maschio, Antonio; Brunner, Nicolas
Einstein-Podolsky-Rosen steering is a form of inseparability in quantum theory commonly acknowledged to be intermediate between entanglement and Bell nonlocality. However, this statement has so far only been proven for a restricted class of measurements, namely, projective measurements. Here we prove that entanglement, one-way steering, two-way steering, and nonlocality are genuinely different considering general measurements, i.e., single round positive-operator-valued measures. Finally, we show that the use of sequences of measurements is relevant for steering tests, as they can be used to reveal “hidden steering.”
2015-11-11T12:06:43ZQuintino, Marco TulioVértesi, TamasCavalcanti, DanielAugusiak, RemigiuszDemianowicz, MaciejAcín dal Maschio, AntonioBrunner, NicolasEinstein-Podolsky-Rosen steering is a form of inseparability in quantum theory commonly acknowledged to be intermediate between entanglement and Bell nonlocality. However, this statement has so far only been proven for a restricted class of measurements, namely, projective measurements. Here we prove that entanglement, one-way steering, two-way steering, and nonlocality are genuinely different considering general measurements, i.e., single round positive-operator-valued measures. Finally, we show that the use of sequences of measurements is relevant for steering tests, as they can be used to reveal “hidden steering.”Nonlocality in many-body quantum systems detected with two-body correlatorsTura, J.Augusiak, RemigiuszSainz, A. B.Lücke, B.Klempt, C.Lewenstein, MaciejAcín dal Maschio, Antoniohttp://hdl.handle.net/2117/789582022-12-21T08:07:43Z2015-11-10T12:19:08ZNonlocality in many-body quantum systems detected with two-body correlators
Tura, J.; Augusiak, Remigiusz; Sainz, A. B.; Lücke, B.; Klempt, C.; Lewenstein, Maciej; Acín dal Maschio, Antonio
Contemporary understanding of correlations in quantum many-body systems and in quantum phase transitions
is based to a large extent on the recent intensive studies of entanglement in many-body systems. In contrast,
much less is known about the role of quantum nonlocality in these systems, mostly because the available
multipartite Bell inequalities involve high-order correlations among many particles, which are hard to access
theoretically, and even harder experimentally. Standard, ”theorist- and experimentalist-friendly” many-body
observables involve correlations among only few (one, two, rarely three...) particles. Typically, there is no
multipartite Bell inequality for this scenario based on such low-order correlations. Recently, however, we have
succeeded in constructing multipartite Bell inequalities that involve two- and one-body correlations only, and
showed how they revealed the nonlocality in many-body systems relevant for nuclear and atomic physics [Science
344, 1256 (2014)]. With the present contribution we continue our work on this problem. On the one hand,
we present a detailed derivation of the above Bell inequalities, pertaining to permutation symmetry among the
involved parties. On the other hand, we present a couple of new results concerning such Bell inequalities. First,
we characterize their tightness. We then discuss maximal quantum violations of these inequalities in the general
case, and their scaling with the number of parties. Moreover, we provide new classes of two-body Bell inequalities
which reveal nonlocality of the Dicke states—ground states of physically relevant and experimentally
realizable Hamiltonians. Finally, we shortly discuss various scenarios for nonlocality detection in mesoscopic
systems of trapped ions or atoms, and by atoms trapped in the vicinity of designed nanostructures.
2015-11-10T12:19:08ZTura, J.Augusiak, RemigiuszSainz, A. B.Lücke, B.Klempt, C.Lewenstein, MaciejAcín dal Maschio, AntonioContemporary understanding of correlations in quantum many-body systems and in quantum phase transitions
is based to a large extent on the recent intensive studies of entanglement in many-body systems. In contrast,
much less is known about the role of quantum nonlocality in these systems, mostly because the available
multipartite Bell inequalities involve high-order correlations among many particles, which are hard to access
theoretically, and even harder experimentally. Standard, ”theorist- and experimentalist-friendly” many-body
observables involve correlations among only few (one, two, rarely three...) particles. Typically, there is no
multipartite Bell inequality for this scenario based on such low-order correlations. Recently, however, we have
succeeded in constructing multipartite Bell inequalities that involve two- and one-body correlations only, and
showed how they revealed the nonlocality in many-body systems relevant for nuclear and atomic physics [Science
344, 1256 (2014)]. With the present contribution we continue our work on this problem. On the one hand,
we present a detailed derivation of the above Bell inequalities, pertaining to permutation symmetry among the
involved parties. On the other hand, we present a couple of new results concerning such Bell inequalities. First,
we characterize their tightness. We then discuss maximal quantum violations of these inequalities in the general
case, and their scaling with the number of parties. Moreover, we provide new classes of two-body Bell inequalities
which reveal nonlocality of the Dicke states—ground states of physically relevant and experimentally
realizable Hamiltonians. Finally, we shortly discuss various scenarios for nonlocality detection in mesoscopic
systems of trapped ions or atoms, and by atoms trapped in the vicinity of designed nanostructures.Quench dynamics of dipolar fermions in a one-dimensional harmonic trapGraß, Tobiashttp://hdl.handle.net/2117/789432020-07-22T18:04:24Z2015-11-09T16:32:24ZQuench dynamics of dipolar fermions in a one-dimensional harmonic trap
Graß, Tobias
We study a system of few fermions in a one-dimensional harmonic trap and focus on the case of dipolar
majority particles in contact with a single impurity. The impurity is used both for quenching the system and
for tracking the system evolution after the quench. Employing exact diagonalization, we investigate relaxation
and thermalization properties. In the absence of dipolar interactions, the system dynamics remains oscillatory
even on long time scales. On the other hand, repulsive as well as attractive dipolar interactions lead to quick
relaxation to the diagonal ensemble average, which is significantly different from corresponding thermal averages.
A Wigner-shaped level spacing distribution indicates level repulsion and thus chaotic dynamical behavior due to
the presence of dipolar interactions.
2015-11-09T16:32:24ZGraß, TobiasWe study a system of few fermions in a one-dimensional harmonic trap and focus on the case of dipolar
majority particles in contact with a single impurity. The impurity is used both for quenching the system and
for tracking the system evolution after the quench. Employing exact diagonalization, we investigate relaxation
and thermalization properties. In the absence of dipolar interactions, the system dynamics remains oscillatory
even on long time scales. On the other hand, repulsive as well as attractive dipolar interactions lead to quick
relaxation to the diagonal ensemble average, which is significantly different from corresponding thermal averages.
A Wigner-shaped level spacing distribution indicates level repulsion and thus chaotic dynamical behavior due to
the presence of dipolar interactions.