arXiv subjects

Anton Kalinin

Publications and source records attributed to Anton Kalinin.

10 recordsLinked to original sources

arXiv2026

Surrogate neutron-capture studies with fission detection in inverse kinematics at the ESR storage ring

The NECTAR (Nuclear rEaCTions At storage Rings) experiment at the ESR heavy-ion storage ring at GSI/FAIR Darmstadt is dedicated to surrogate reaction studies of neutron-induced reactions on heavy nuclei in inverse kinematics. In this work, we report on the implementation and performance of a newly developed fission-fragment detection system integrated into the NECTAR experimental setup. The upgraded detector configuration enables, for the first time in a surrogate experiment, the simultaneous detection ofgamma-decay residues, multi-neutron-emission residues, and fission fragments. The full setup was used for the first time in an experiment where a stored beam of bare 238U92+ ions at 17.24 MeV/u interacted with a gas-jet deuterium target, populating excited 238U and 239U nuclei via the 238U(d,d') and 238U(d,p) reactions. We describe the geometry of the used fission fragment detectors, design constraints, and simulation-based efficiency determination. The target-like particle identification and beam-like residue spectra demonstrating the performance of the complete setup are also shown.

physics.ins-det↗

arXiv2024

Quantum Electrodynamics in Strong Electromagnetic Fields: Substate Resolved K$α$ Transition Energies in Helium-like Uranium

Using novel metallic magnetic calorimeter detectors at the CRYRING@ESR, we recorded X-ray spectra of stored and electron cooled helium-like uranium (U$^{90+}$) with an unmatched spectral resolution of close to 90 eV. This allowed for an accurate determination of the energies of all four components of the K$α$ transitions in U$^{90+}$. We find good agreement with state-of-the-art bound-state QED calculations for the strong-field regime. Our results do not support any systematic deviation between experiment and theory in helium-like systems, the presence of which was subject of intense debates in recent years.

physics.atom-ph↗

arXiv2020

Swirling the weakly bound helium dimer from inside

Controlling the interactions between atoms with external fields opened up new branches in physics ranging from strongly correlated atomic systems to ideal Bose and Fermi gases and Efimov physics. Such control usually prepares samples that are stationary or evolve adiabatically in time. On the other hand, in molecular physics external ultrashort laser fields are employed to create anisotropic potentials that launch ultrafast rotational wave packets and align molecules in free space. Here we combine these two regimes of ultrafast times and low energies. We apply a short laser pulse to the helium dimer, a weakly bound and highly delocalized single bound state quantum system. The laser field locally tunes the interaction between two helium atoms, imparting an angular momentum of $2\hbar$ and evoking an initially confined dissociative wave packet. We record a movie of the density and phase of this wave packet as it evolves from the inside out. At large internuclear distances, where the interaction between the two helium atoms is negligible, the wave packet is essentially free. This work paves the way for future tomography of wave packet dynamics and provides the technique for studying exotic and otherwise hardly accessible quantum systems such as halo and Efimov states.

physics.atm-clus↗

arXiv2020

Towards experiments with highly charged ions at HESR

The atomic physic collaboration SPARC is a part of the APPA pillar at the future Facility for Antiproton and Ion Research. It aims for atomic-physics research across virtually the full range of atomic matter. A research area of the atomic physics experiments is the study of the collision dynamics in strong electro-magnetic fields as well as the fundamental interactions between electrons and heavy nuclei at the HESR. Here we give a short overview about the central instruments for SPARC experiments at this storage ring.

physics.atom-ph↗

arXiv2020

Crystal growth rates in supercooled atomic liquid mixtures

Crystallization is a fundamental process in materials science, providing the primary route for the realization of a wide range of new materials. Crystallization rates are also considered to be useful probes of glass-forming ability. At the microscopic level, crystallization is described by the classical crystal nucleation and growth theories, yet in general solid formation is a far more complex process. In particular, the observation of apparently different crystal growth regimes in many binary liquid mixtures greatly challenges our understanding of crystallization. Here, we study by experiments, theory and computer simulations the crystallization of supercooled mixtures of argon and krypton, showing that crystal growth rates in these systems can be reconciled with existing crystal growth models only by explicitly accounting for the non-ideality of the mixtures. Our results highlight the importance of thermodynamic aspects in describing the crystal growth kinetics, providing a substantial step towards a more sophisticated theory of crystal growth.

cond-mat.mtrl-sci↗

arXiv2018

Double-slit photoelectron interference in strong-field ionization of the neon dimer

Wave-particle duality is an inherent peculiarity of the quantum world. The double-slit experiment has been frequently used for understanding different aspects of this fundamental concept. The occurrence of interference rests on the lack of which-way information and on the absence of decoherence mechanisms, which could scramble the wave fronts. In this letter, we report on the observation of two-center interference in the molecular frame photoelectron momentum distribution upon ionization of the neon dimer by a strong laser field. Postselection of ions, which were measured in coincidence with electrons, allowed choosing the symmetry of the continuum electronic wave function, leading to observation of both, gerade and ungerade, types of interference.

physics.atom-ph↗

arXiv2017

Shrinking of Rapidly Evaporating Water Microdroplets Reveals their Extreme Supercooling

The fast evaporative cooling of micrometer-sized water droplets in vacuum offers the appealing possibility to investigate supercooled water - below the melting point but still a liquid - at temperatures far beyond the state-of-the-art. However, it is challenging to obtain a reliable value of the droplet temperature under such extreme experimental conditions. Here, the observation of morphology-dependent resonances in the Raman scattering from a stream of perfectly uniform water droplets has allowed us to measure with an absolute precision of better than 0.2% the variation in droplet size resulting from evaporative mass losses. This finding proved crucial to an unambiguous determination of the droplet temperature. In particular, a fraction of water droplets with initial diameter of 6379$\pm$12 nm were found to remain liquid down to 230.6$\pm$0.6 K. Our results question temperature estimates reported recently for larger supercooled water droplets, and provide valuable information on the hydrogen-bond network in liquid water in the hard-to-access deeply supercooled regime.

cond-mat.other↗

arXiv2017

Electron spin polarization in strong-field ionization of Xenon atoms

As a fundamental property of the electron, the spin plays a decisive role in the electronic structure of matter from solids to molecules and atoms, e.g. causing magnetism. Yet, despite its importance, the spin dynamics of electrons released during the interaction of atoms with strong ultrashort laser pulses has remained unexplored. Here we report on the experimental detection of electron spin polarization by strong-field ionization of Xenon atoms and support our results by theoretical analysis. We found up to 30% spin polarization changing its sign with electron energy. This work opens the new dimension of spin to strong-field physics. It paves the way to production of subfemtosecond spin polarized electron pulses with applications ranging from probing magnetic properties of matter at ultrafast time scales to testing chiral molecular systems with subfemtosecond temporal and sub-Ångström spatial resolution.

physics.atom-ph↗

arXiv2015

Observation of the Efimov state of the helium trimer

Quantum theory dictates that upon weakening the two-body interaction in a three-body system, an infinite number of three-body bound states of a huge spatial extent emerge just before these three-body states become unbound. Three helium atoms have been predicted to form a molecular system that manifests this peculiarity under natural conditions without artificial tuning of the attraction between particles by an external field. Here we report experimental observation of this long predicted but experimentally elusive Efimov state of $^{4}$He$_{3}$ by means of Coulomb explosion imaging. We show spatial images of an Efimov state, confirming the predicted size and a typical structure where two atoms are close to each other while the third is far away.

physics.atm-clus↗

arXiv2014

Observation of crystallization slowdown in supercooled para-hydrogen and ortho-deuterium quantum liquid mixtures

We report a quantitative experimental study of the crystallization kinetics of supercooled quantum liquid mixtures of para-hydrogen (pH$_2$) and ortho-deuterium (oD$_2$) by high spatial resolution Raman spectroscopy of liquid microjets. We show that in a wide range of compositions the crystallization rate of the isotopic mixtures is significantly reduced with respect to that of the pure substances. To clarify this behavior we have performed path-integral simulations of the non-equilibrium pH$_2$-oD$_2$ liquid mixtures, revealing that differences in quantum delocalization between the two isotopic species translate into different effective particle sizes. Our results provide first experimental evidence for crystallization slowdown of quantum origin, offering a benchmark for theoretical studies of quantum behavior in supercooled liquids.

cond-mat.other↗