Daniel Pęcak
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View article: Dynamical scheme for computing the mass parameter of a system in a medium
Dynamical scheme for computing the mass parameter of a system in a medium Open
We present a new method for extracting a mass parameter using time-dependent density functional theory for an arbitrary physical system, provided the adiabatic limit is achievable. This approach works for collective variables also in the p…
View article: Stability conditions for bound states in antiprotonic atoms
Stability conditions for bound states in antiprotonic atoms Open
We study the stability of bound antiprotons in close proximity to the atomic nucleus. Using experimental data from x-ray spectroscopy measurements of antiprotonic atom transitions, we tune a minimal theoretical framework and estimate param…
View article: Positron-Positronium Converters in Reflection and Transmission Geometry for Gravitational Experiments with Antihydrogen using Moiré Deflectometry
Positron-Positronium Converters in Reflection and Transmission Geometry for Gravitational Experiments with Antihydrogen using Moiré Deflectometry Open
In the context of the Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy (AEgIS) located at CERN, positron-positronium converters with a high positron-positronium conversion efficiency have been designed in both reflection and …
View article: Laser Cooling Positronium with Broadband Laser Pulses
Laser Cooling Positronium with Broadband Laser Pulses Open
The first successful demonstration of broadband laser cooling of positronium (Ps) atoms, obtained within the AEgIS experiment at CERN, is presented here. By employing a custom-designed pulsed alexandrite laser system at 243 nm featuring lo…
View article: Real-time antiproton annihilation vertexing with submicrometer resolution
Real-time antiproton annihilation vertexing with submicrometer resolution Open
Primary goal of the AEḡIS experiment is to precisely measure the free fall of antihydrogen within Earth’s gravitational field. To this end, cold (≈50 K) antihydrogen will traverse a two-grid moiré deflectometer before annihilating onto a p…
View article: Positronium Doppler laser cooling: results and perspectives
Positronium Doppler laser cooling: results and perspectives Open
The experimental demonstration of positronium laser cooling with stationary broadband laser pulses with negative detuning is briefly described. Considerations on the limits of the current experiment and possible future developments follow.…
View article: The AEgIS Experiment: Progress and Future Outlook
The AEgIS Experiment: Progress and Future Outlook Open
The AEgIS experiment at CERN is pioneering measurements of gravity, spectroscopy, and interferometry using pulsed antimatter atomic sources. This work provides an overview of the AEgIS experimental setup and highlights recent advancements …
View article: Prospects for forward emitted positronium from nanoporous membranes at AEgIS
Prospects for forward emitted positronium from nanoporous membranes at AEgIS Open
Antihydrogen formation at AEgIS at CERN leverages charge exchange between Rydberg positronium (Ps*) and antiprotons, with cross-sections scaling with the Ps principal quantum number $n^4$ and inversely with relative velocity $v^{-2}$. Howe…
View article: Time-Dependent Nuclear Energy-Density Functional Theory Toolkit for Neutron Star Crust: Dynamics of a Nucleus in a Neutron Superfluid
Time-Dependent Nuclear Energy-Density Functional Theory Toolkit for Neutron Star Crust: Dynamics of a Nucleus in a Neutron Superfluid Open
We present a new numerical tool designed to probe the dense layers of neutron star crusts. It is based on the time-dependent Hartree-Fock-Bogoliubov theory with generalized Skyrme nuclear energy-density functionals of the Brussels-Montreal…
View article: Spin-flip-induced quadrupole resonance in odd-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>A</mml:mi></mml:math> exotic atoms
Spin-flip-induced quadrupole resonance in odd- exotic atoms Open
We examine the possible existence of quadrupole resonances in exotic atoms containing odd-A nuclei. We find that the spin flip of the deexciting exotic particle can induce a resonance, altering the orbital angular momentum of the nucleus b…
View article: Real-time antiproton annihilation vertexing with sub-micron resolution
Real-time antiproton annihilation vertexing with sub-micron resolution Open
The primary goal of the AEgIS experiment is to precisely measure the free fall of antihydrogen within Earth's gravitational field. To this end, a cold ~50K antihydrogen beam has to pass through two grids forming a moiré deflectometer befor…
View article: Quantum vortices in fermionic superfluids: from ultracold atoms to neutron stars
Quantum vortices in fermionic superfluids: from ultracold atoms to neutron stars Open
Superfluid dilute neutron matter and ultracold gas, close to the unitary regime, exhibit several similarities. Therefore, to a certain extent, fermionic ultracold gases may serve as emulators of dilute neutron matter, which forms the inner…
View article: Time-dependent nuclear energy-density functional theory toolkit for neutron star crust: Dynamics of a nucleus in a neutron superfluid
Time-dependent nuclear energy-density functional theory toolkit for neutron star crust: Dynamics of a nucleus in a neutron superfluid Open
We present a new numerical tool designed to probe the dense layers of neutron star crusts. It is based on the time-dependent Hartree-Fock-Bogoliubov theory with generalized Skyrme nuclear energy-density functionals of the Brussels-Montreal…
View article: The spin-flip-induced quadrupole resonance in odd-$A$ exotic atoms
The spin-flip-induced quadrupole resonance in odd-$A$ exotic atoms Open
We examine the possible existence of quadrupole resonances in exotic atoms containing odd-$A$ nuclei. We find that the spin-flip of the de-exciting exotic particle can induce a resonance, altering the orbital angular momentum of the nucleu…
View article: Dataset for 'Unconventional pairing in few-fermion systems at finite temperature'
Dataset for 'Unconventional pairing in few-fermion systems at finite temperature' Open
This package provides all data that has been used to create plots in'Unconventional pairing in few-fermion systems at finite temperature',D. Pęcak, T. Sowiński; Scientific Reports 12, 17476 (2022) https://www.nature.com/articles/s41598-022…
View article: Dataset for 'Unconventional pairing in few-fermion systems at finite temperature'
Dataset for 'Unconventional pairing in few-fermion systems at finite temperature' Open
This package provides all data that has been used to create plots in'Unconventional pairing in few-fermion systems at finite temperature',D. Pęcak, T. Sowiński; Scientific Reports 12, 17476 (2022) https://www.nature.com/articles/s41598-022…
View article: Atomic boson-fermion mixtures in one-dimensional box potentials: Few-body and mean-field many-body analyses
Atomic boson-fermion mixtures in one-dimensional box potentials: Few-body and mean-field many-body analyses Open
We study binary atomic boson-fermion mixtures confined in one dimensional box potentials by few-body theory with contact interactions and mean-field many-body theory with density-density interactions. A variety of correlations and structur…
View article: Atomic boson-fermion mixtures in 1D box potentials: Few-body and mean-field many-body analyses
Atomic boson-fermion mixtures in 1D box potentials: Few-body and mean-field many-body analyses Open
We study binary atomic boson-fermion mixtures confined in one dimensional box potentials by few-body theory with contact interactions and mean-field many-body theory with density-density interactions. A variety of correlations and structur…
View article: Signatures of unconventional pairing in spin-imbalanced one-dimensional few-fermion systems
Signatures of unconventional pairing in spin-imbalanced one-dimensional few-fermion systems Open
A system of a few attractively interacting fermionic $^6$Li atoms in one-dimensional harmonic confinement is investigated. Non-trivial inter-particle correlations induced by interactions in a particle-imbalanced system are studied in the f…
View article: Geometry-induced entanglement in a mass-imbalanced few-fermion system
Geometry-induced entanglement in a mass-imbalanced few-fermion system Open
Many-body systems undergoing quantum phase transitions reveal substantial\ngrowth of non-classical correlations between different parties of the system.\nThis behavior is manifested by characteristic divergences of the von Neumann\nentropy…
View article: Mass-imbalance-induced structures of binary atomic mixtures in box potentials
Mass-imbalance-induced structures of binary atomic mixtures in box potentials Open
We consider the ground states of binary atomic boson-boson and fermion-fermion mixtures confined in one-dimensional box potentials by simulating the systems using few-body models with delta-function interactions and many-body models with d…
View article: Global optimization for quantum dynamics of few-fermion systems
Global optimization for quantum dynamics of few-fermion systems Open
Quantum state preparation is vital to quantum computation and quantum information processing tasks. In adiabatic state preparation, the target state is theoretically obtained with nearly perfect fidelity if the control parameter is tuned s…
View article: Four fermions in a one-dimensional harmonic trap: Accuracy of a variational-ansatz approach
Four fermions in a one-dimensional harmonic trap: Accuracy of a variational-ansatz approach Open
Detailed analysis of the system of four interacting ultra-cold fermions confined in a one-dimensional harmonic trap is performed. The analysis is done in the framework of a simple variational ansatz for the many-body ground state and its p…
View article: Few strongly interacting ultracold fermions in one-dimensional traps of different shapes
Few strongly interacting ultracold fermions in one-dimensional traps of different shapes Open
The ground-state properties of a few spin-1/2 fermions with different masses\nand interacting via short-range contact forces are studied within an exact\ndiagonalization approach. It is shown that, depending on the shape of the\nexternal c…
View article: Spatial separation and its transition in a one-dimensional system of a few fermions
Spatial separation and its transition in a one-dimensional system of a few fermions Open
The ground-state properties of a two-component mixture of a few fermions with different masses are studied within an exact diagonalization approach. It is shown that depending on the shape of the external confinement, different scenarios o…
View article: Multimode Raman light-atom interface in warm atomic ensemble as multiple three-mode quantum operations
Multimode Raman light-atom interface in warm atomic ensemble as multiple three-mode quantum operations Open
We analyze the properties of a Raman quantum light-atom interface in long atomic ensemble and its applications as a quantum memory or two-mode squeezed state generator. We consider the weak-coupling regime and include both Stokes and anti-…