K. Kowalik
A5105768551- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Quantum Chromodynamics and Particle Interactions
- Astrophysics and Cosmic Phenomena
- Semiconductor Quantum Structures and Devices
- Quantum and electron transport phenomena
- Quantum Dots Synthesis And Properties
- Particle Detector Development and Performance
- Particle accelerators and beam dynamics
- Advanced Semiconductor Detectors and Materials
- Dark Matter and Cosmic Phenomena
- Semiconductor Lasers and Optical Devices
- Physics of Superconductivity and Magnetism
- Chalcogenide Semiconductor Thin Films
- Nuclear reactor physics and engineering
- Electronic and Structural Properties of Oxides
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Radiation Detection and Scintillator Technologies
- Muon and positron interactions and applications
- Semiconductor materials and devices
- Quantum optics and atomic interactions
- Gamma-ray bursts and supernovae
- Quantum Information and Cryptography
National Centre for Nuclear Research
2015-2025
Duke University
2018-2023
Universidad Autónoma de Madrid
2018-2023
University of California, Irvine
2013-2023
Albert Einstein College of Medicine
2023
Colorado State University
2011-2023
Boston University
2013-2023
University of Bern
2023
Eötvös Loránd University
2023
University of Belgrade
2017-2019
The fine structure of the neutral exciton in a single self assembled InGaAs quantum dot is investigated under effect lateral electric field. Stark shifts up to 1.5 meV, an increase linewidth, and decrease photoluminescence intensity were observed due We show that field strongly affects splitting active manipulation particle wave-functions. Remarkably, can be tuned over large values through zero.
Measurements of inclusive spectra and mean multiplicities $$\pi ^\pm $$ , K $$^\pm p $${\bar{\text {p}}}$$ produced in inelastic + interactions at incident projectile momenta 20, 31, 40, 80 158 $$\text{ GeV }/c$$ ( $$\sqrt{s} = 6.3, 7.7, 8.8, 12.3 17.3 }$$ respectively) were performed the CERN Super Proton Synchrotron using large acceptance NA61/SHINE hadron spectrometer. Spectra are presented as function rapidity transverse momentum compared to predictions current models. The measurements...
Measurements of hadron production in p + C interactions at 31 GeV/c are performed using the NA61/SHINE spectrometer CERN SPS. The analysis is based on full set data collected 2009 a graphite target with thickness 4 % nuclear interaction length. Inelastic and cross sections as well spectra $$\pi ^{\pm }$$ , $$K^{\pm p, $$K^0_S$$ $$\varLambda $$ measured high precision. These measurements essential for improved calculations initial neutrino fluxes T2K long-baseline oscillation experiment...
The influence of an in-plane electric field on the optical properties single quantum dots is investigated. On a sample containing plane InAs∕GaAs dots, micrometer-size electro-optical structures were produced in order to apply external dot plane. A large decrease anisotropic exchange splitting, correlated with Stark shift, observed.
We report on the dynamic nuclear polarization of a single charge-tunable self-assembled $\mathrm{InAs}∕\mathrm{GaAs}$ quantum dot in longitudinal magnetic field $\ensuremath{\sim}0.2\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. The hyperfine interaction between optically oriented electron and spins leads to nuclei measured by Overhauser shift singly charged excitons (${X}^{+}$ ${X}^{\ensuremath{-}}$). When going from ${X}^{+}$ ${X}^{\ensuremath{-}}$, we observe reversal this shift, which reflects...
We present a measurement of the longitudinal spin cross section asymmetry for deep-inelastic muon-nucleon interactions with two high transverse momentum hadrons in final state. Two methods event classification are used to increase contribution photon-gluon fusion process above 30%. The most effective one, based on neural network approach, provides asymmetries Al→NlhhXp=0.030±0.057(stat)±0.010(syst) and Al→NlhhXd=0.070±0.076(stat)±0.010(syst). From these values we derive an averaged gluon...
Measurements of multiplicity and transverse momentum fluctuations charged particles were performed in inelastic p+p interactions at 20, 31, 40, 80, 158 $$\text{ GeV }\!/\!c$$ beam momentum. Results for the scaled variance distribution three strongly intensive measures $$\varDelta [P_{T},N]$$ , $$\varSigma $$\varPhi _{p_T}$$ are presented. For first time results on fully corrected experimental biases. The significantly deviate from expectations independent particle production. They also...
Systematic measurements of auto- and cross-correlations photons emitted from individual $\mathrm{Cd}\mathrm{Te}∕\mathrm{Zn}\mathrm{Te}$ quantum dots under pulsed excitation were used to elucidate nonresonant mechanisms in this self-assembled system. Memory effects extending over a few pulses have been detected agreement with previous reports quantitatively described by rate equation model, fitting complete set correlation PL intensity results. The important role single carrier trapping the...
Self-assembled magnetic ${\mathrm{Cd}}_{x}{\mathrm{Mn}}_{1\ensuremath{-}x}\mathrm{Te}$ quantum dots (QDs) embedded in nonmagnetic ${\mathrm{Zn}}_{0.6}{\mathrm{Cd}}_{0.4}\mathrm{Te}$ were grown by molecular beam epitaxy. We achieved a large degree of dilution Mn ions inside the QDs, ${x}_{\mathrm{Mn}}=0.003$, which allowed us to study single QDs containing only few ions. The insight into properties these structures was obtained performing measurements photoluminescence an external field with...
Measurements of particle emission from a replica the T2K 90 cm-long carbon target were performed in NA61/SHINE experiment at CERN SPS, using data collected during high-statistics run 2009. An efficient use long-target measurements for neutrino flux predictions requires dedicated reconstruction and analysis techniques. Fully-corrected differential yields $$\pi ^\pm $$ -mesons surface incoming 31 GeV/c protons are presented. A possible strategy to implement these results into beam is discussed...
Measurements of the $\pi^{\pm}$, $K^{\pm}$, and proton double differential yields emitted from surface 90-cm-long carbon target (T2K replica) were performed for incoming 31 GeV/c protons with NA61/SHINE spectrometer at CERN SPS using data collected during 2010 run. The $\pi^{\pm}$ measured increased precision compared to previously published results, while $K^{\pm}$ obtained first time. A strategy dealing dependence results on beam profile is proposed. purpose these measurements reduce...
We report on the growth and high spatial resolution magneto-photoluminescence of CdMnTe quantum dots embedded in a ZnCdTe matrix with Mn content about 3%. The giant Zeeman spitting excitonic emission coming from individual magnetization fluctuations inside them are studied magnetic fields up to 7 T. have found that description these effects requires inclusion antiferromagnetic Mn–Mn interaction considerations. Moreover, values shift strongly related size dot. In particular, higher spectral...
We investigate exciton spin memory in individual $\mathrm{In}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ self-assembled quantum dots via optical alignment and conversion of polarization a magnetic field. Quasiresonant phonon-assisted excitation is successfully employed to define the initial neutral excitons. The conservation linear generated along bright eigenaxes up 90% from circular 47% both demonstrate very long relaxation time with respect radiative lifetime. Results are quantitatively compared...
Polarization-resolved photoluminescence (PL) spectroscopy of individual $\mathrm{Cd}\mathrm{Te}∕\mathrm{Zn}\mathrm{Te}$ quantum dots is investigated in the presence external in-plane magnetic field. We find that applied field modifies excitonic fine structure, depending on dot anisotropy direction (which randomly oriented this system). The splitting between ``bright'' and ``dark'' states increases with field, whereas anisotropic exchange bright excitons can be reduced or enhanced, for...
We use optical orientation technique to monitor the degeneracy control of exciton states in a single InAs∕GaAs quantum dot, achieved by applying an in-plane electric field. Under circularly polarized quasiresonant excitation, photoluminescence shows pronounced maximum circular polarization at field corresponding zero fine structure splitting. By analyzing width this we are able determine homogeneous linewidth excitonic transition. This experimental method is shown be very efficient test and...
Inclusive production of $Λ$-hyperons was measured with the large acceptance NA61/SHINE spectrometer at CERN SPS in inelastic p+p interactions beam momentum 158~\GeVc. Spectra transverse and mass as well distributions rapidity x$_{_F}$ are presented. The mean multiplicity estimated to be $0.120\,\pm0.006\;(stat.)\,\pm 0.010\;(sys.)$. results compared previous measurements predictions EPOS, UrQMD FRITIOF models.
We present measurements of $$\rho ^0$$ , $$\omega $$ and K $$^{*0}$$ spectra in $$\pi ^{-} + C production interactions at 158 $$\text{ GeV }{/}\text{ c }$$ 350 using the NA61/SHINE spectrometer CERN SPS. Spectra are presented as a function Feynman's variable $$x_\text {F}$$ range $$0< x_\text {F} < 1$$ 0.5$$ for respectively. Furthermore, we show comparisons with previous predictions several hadronic interaction models. These essential better understanding shower development improving...
This paper presents measurements of production cross sections and inelastic for the following reactions: $60\text{ }\text{ }\mathrm{GeV}/c$ protons with C, Be, Al targets $120\text{ C Be targets. The analysis is performed using NA61/SHINE spectrometer at CERN Super Proton Synchrotron. First are obtained }\mathrm{GeV}/c$, while results compared previously published measurements. These interaction section critical inputs neutrino flux prediction in current future accelerator-based...
Abstract Results on $$\phi $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ϕ</mml:mi></mml:math> meson production in inelastic $$p + p$$ xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>p</mml:mi><mml:mo>+</mml:mo><mml:mi>p</mml:mi></mml:mrow></mml:math> collisions at CERN SPS energies are presented. They derived from data collected by the NA61/SHINE fixed target experiment, means of invariant mass spectra fits \rightarrow K^+ K^-...
Abstract We present results of polarization‐resolved micro‐photoluminescence (μ‐PL) experiments on self‐organized InAs/GaAs (QDs). have investigated how Coulomb interactions are modified by application an electric field. observed systematic variation bright exciton splitting for different field configurations (applied in the quantum dot plane or along sample growth axis). The show also dependence direct carriers inside dots, manifested changes PL line position charged excitons (X + and X ‐ )...
We examine the diamagnetic contribution to effect of an in-plane magnetic field on excitonic fine structure in quantum dots. Magnetic compression wave function direction perpendicular modifies long-range exchange interaction and can contribute cancellation anisotropic splitting. Numerical estimates indicate that this orbital be comparable with Zeeman spin should play a significant role usual experimental configurations.
Polarization-resolved magnetoluminescence, together with simultaneous magnetotransport measurements, have been performed on a two-dimensional electron gas (2DEG) confined in CdTe quantum well order to determine the spin splitting of fully occupied electronic Landau levels, as function magnetic field (arbitrary Landau-level filling factors) and temperature. The splitting, extracted from energy separation ${\ensuremath{\sigma}}^{+}$ ${\ensuremath{\sigma}}^{\ensuremath{-}}$ transitions, is...
This paper presents several measurements of total production cross sections and inelastic for the following reactions: ${\ensuremath{\pi}}^{+}+\mathrm{C}$, ${\ensuremath{\pi}}^{+}+\mathrm{Al}$, ${K}^{+}+\mathrm{C}$, ${K}^{+}+\mathrm{Al}$ at $60\text{ }\text{ }\mathrm{GeV}/c$, ${\ensuremath{\pi}}^{+}+\mathrm{C}$ ${\ensuremath{\pi}}^{+}+\mathrm{Al}$ $31\text{ }\mathrm{GeV}/c$. The were made using NA61/SPS Heavy Ion Neutrino Experiment spectrometer CERN Super Proton Synchrotron (SPS)....