arXiv subjects

Peter Jeglič

Publications and source records attributed to Peter Jeglič.

9 recordsLinked to original sources

arXiv2024

Incommensurable matter-wave jets in quasi-1D geometry

Matter-wave jets are ejected from a Bose-Einstein condensate subjected to a modulation of the interaction strength. For sufficiently strong modulation additional higher harmonic matter-wave jets emerge. Here we report the first experimental observation of incommensurable "golden" $\frac{1+\sqrt{5}}{2}$ matter-wave jets in a Bose-Einstein condensate exposed to a single frequency interaction modulation. We study the formation of higher-order jets and the corresponding incommensurable density waves in quasi-one-dimensional geometry with numerical one dimensional (1D) Gross-Pitaevskii equation simulation. We explore the process of jet formation experimentally and theoretically for a wide range of modulation amplitudes and frequencies and establish a phase diagram delineating different regimes of jet formation.

cond-mat.quant-gas↗

arXiv2023

Suppression of dark-state polariton collapses in cold-atom quantum memory

We observe dark-state polariton collapses and revivals in a quantum memory based on electromagnetically induced transparency on a cloud of cold cesium atoms in a magnetic field. Using $σ^+$ polarized signal and control beams in the direction of the magnetic field, we suppress the dark-state polariton collapses by polarizing the atoms towards one of the stretched Zeeman states and optimizing the frequency detuning of the control beam. In this way, we demonstrate a quantum memory with only partial dark-state polariton collapses, making the memory usable at any storage time, not only at discretized times of revivals. We obtain storage time of more than 400 $\rmμ$s, which is ten times longer than what we can achieve by trying to annul the magnetic field.

quant-ph↗

arXiv2022

Preparation of ultra-cold atomic-ensemble arrays using time-multiplexed optical tweezers

We use optical tweezers based on time-multiplexed acousto-optic deflectors to trap ultra-cold cesium atoms in one-dimensional arrays of atomic ensembles. For temperatures between 2.5 $μ$K and 50 nK we study the maximal time between optical tweezer pulses that retains the number of atoms in a single trap. This time provides an estimate on the maximal number of sites in an array of time-multiplexed optical tweezers. We demonstrate evaporative cooling of atoms in arrays of up to 25 optical tweezer traps and the preparation of atoms in a box potential. Additionally, we demonstrate three different protocols for the preparation of atomic-ensemble arrays by transfer from an expanding ultra-cold atomic cloud. These result in the preparation of arrays of up to 74 atomic ensembles consisting of $\sim$100 atoms on average.

physics.atom-ph↗

arXiv2021

Single-shot Stern-Gerlach magnetic gradiometer with an expanding cloud of cold cesium atoms

We combine the Ramsey interferometry protocol, the Stern-Gerlach detection scheme, and the use of elongated geometry of a cloud of fully polarized cold cesium atoms to measure the selected component of the magnetic field gradient along the atomic cloud in a single shot. In contrast to the standard method where the precession of two spatially separated atomic clouds is simultaneously measured to extract their phase difference, which is proportional to the magnetic field gradient, we here demonstrate a gradiometer using a single image of an expanding atomic cloud with the phase difference imprinted along the cloud. Using resonant radio-frequency pulses and Stern-Gerlach imaging, we first demonstrate nutation and Larmor precession of atomic magnetization in an applied magnetic field. Next, we let the cold atom cloud expand in one dimension and apply the protocol for measuring the magnetic field gradient. The resolution of our single-shot gradiometer is not limited by thermal motion of atoms and has an estimated absolute accuracy below $\pm0.2$~mG/cm ($\pm20$~nT/cm).

physics.atom-ph↗

arXiv2020

Metallic State in Rubidium-Loaded Low-Silica X zeolite

The ground state of alkali metals when the particle size decreases from bulk to nanometric atomic clusters is inevitably accompanied by quantum effects that can suppress their pristine metallic state. We demonstrate that the metallic nature of rubidium clusters confined and arrayed in the framework of insulating low-silica X zeolite is preserved. The $^{87}$Rb NMR spin-lattice relaxation assigned to rubidium clusters in supercages shows a Korringa behavior from 190~K down to 10~K, which is compatible with a macroscopic observation of low electrical resistivity. The density of states at the Fermi level is found to be enhanced compared to the analogous sodium case, consistent with a Holstein-Hubbard model of alkali-loaded zeolites.

cond-mat.str-el↗

arXiv2020

Emission of correlated jets from a driven matter-wave soliton in a quasi-one-dimensional geometry

We demonstrate the emission of correlated atom jets from a matter-wave soliton in a quasi-one-dimensional optical trap. We characterize the dependence of jet properties on the frequency, amplitude and length of the modulation, and qualitatively reproduce the trends in the mean-field picture with a one-dimensional time-dependent Gross-Pitaevskii equation simulation. High-order jets are observed for sufficiently long pulses. A double-pulse modulation sequence produces consecutive jets, and a multi-pulse sequence may lead to irregular 3D jets at a finite angle to the direction of the channel. In the limit of vanishing high-order jets beyond-mean-field number correlations of jet pairs are demonstrated, implying possible number squeezing.

cond-mat.quant-gas↗

arXiv2019

Cesium bright matter-wave solitons and soliton trains

A study of bright matter-wave solitons of a cesium Bose-Einstein condensate (BEC) is presented. Production of a single soliton is demonstrated and dependence of soliton atom number on the interatomic interaction is investigated. Formation of soliton trains in the quasi one-dimensional confinement is shown. Additionally, fragmentation of a BEC has been observed outside confinement, in free space. In the end a double BEC production setup for studying soliton collisions is described.

cond-mat.quant-gas↗

arXiv2017

Thermally Activated Motion of Sodium Cations in Insulating Parent Low-Silica X Zeolite

We report a $^{23}$Na spin-lattice relaxation rate, $T_1^{-1}$, in low-silica X zeolite. $T_1^{-1}$ follows multiple BPP-type behavior as a result of thermal motion of sodium cations in insulating material. The estimated lowest activation energy of 15~meV is much lower than 100~meV observed previously for sodium motion in heavily Na-loaded samples and is most likely attributed to short-distance jumps of sodium cations between sites within the same supercage.

cond-mat.str-el↗

arXiv2012

NMR study of thermally activated paramagnetism in metallic low-silica X zeolite filled with sodium atoms

We report a \^{23}Na and \^{27}Al nuclear magnetic resonance (NMR) investigation of low-silica X (LSX) zeolite with chemical formula Na_{12}Al_{12}Si_{12}O_{48} (Na_{12}-LSX) loaded with n additional guest sodium atoms. Na_{n}/Na_{12}-LSX exhibits an insulator-to-metal transition around n=11.6, which is accompanied by a significant enhancement of bulk magnetic susceptibility. Paramagnetic moments are thermally activated in the metallic Na_{12}/Na_{12}-LSX with an activation energy of around 0.1 eV. At the same time, a new shifted component (SC) appears in the \^{23}Na NMR, whose large and positive NMR shift scales with bulk magnetic susceptibility. Its spin-lattice relaxation rate 1/T_{1} is governed by the fluctuations determined by the same activation energy as obtained from the bulk magnetic susceptibility data. The timescale of these fluctuations is typical for atomic motions, which suggest strong electron-phonon coupling, a hallmark of polaron states. The insulator-to-metal transition in Na_{n}/Na_{12}-LSX is thus discussed within a polaron model.

cond-mat.str-el↗