Stable and narrow-linewidth lasers are critical for high-precision applications in atomic physics, quantum metrology, and optical clocks. Optical cavities serve as high-fidelity frequency references, significantly improving laser frequency stability by providing a well-defined optical resonance. We demonstrated a novel 3D-printed [1] optical cavity shown in Figure [A], using additive...
Circularly polarized light (CPL) induces different populations in left- and righ-handed versions of randomly oriented chiral molecules. Such differences lead to differences in the product yields of photochemical reactions. Thus, CPL triggers all-optical enantioselective photochemistry. But the difference is usually below 0.1%, rendering CPL impractical for photochemical applications....
Arrays of optical tweezers loaded with neutral atoms have rapidly gained traction as a versatile and scalable architecture for quantum information processing. At Eindhoven University of Technology, we are developing a tweezer apparatus that allows control over single- and multi-qubit gates using the Sr clock qubit.
On the poster, we will present our recent experimental results of preparing...
Secondary electron emission is one of the main energy dissipation channels of a highly charged ion impact on a material surface. While the electron yield, i.e. the number of electrons emitted per impacting ion, has been studied extensively for different ion velocities and charge states [1,2], literature on angle- and energy-resolved measurements of low-energy secondary electrons is scarce...
Atomic cascades occur frequently in Nature owing to the interaction of matter with particles and light. Such step-wise changes of an atomic and/or ionic ensemble are often “caused” by either the excitation of inner-shell electrons due to photon, electron, or particle impact, or by the capture of electron(s) into Rydberg orbitals as observed in many astrophysical environments [1].
In practice,...
We present the results of a computational study focusing on the radiation-induced fragmentation dynamics of Fe(CO)₅ precursor molecules on experimentally relevant substrates. A combination of different computational methods is employed, including (i) quantum chemistry methods and (ii) the irradiation-driven molecular dynamics method [1] using the software package MBN Explorer [2]. Following...
We theoretically propose a method to synthesize the first attosecond magnetic pulses with tunable waveform [1]. Our ab initio calculations predict a magnetic pulse with a duration of 787 as and a high flux density of ~1T at a few hundred nanometers from the source, paving the way for attosecond control and measurement of magnetization and chiral dynamics.
[1] A de las Heras et al., J. Phys....
The XCHEM method[1] allows the study of ultrafast processes in anions. At the core of the XCHEM method lies the Gaussian-B-spline basis (GABS)[2], used to represent bound and continuum states. It has been successfully applied to cations, such as neon[2], nitrogen[3] and carbon monoxide[4]. This formalism has started recently to be applied to anions, using nitrogen $N_2^-$ as a benchmark to...
By combining a monochromatic electron source and high performance detectors, we build with ISMO and SPEC a new electronic microscope call HREELM. This microscope enables the imaging and analysis of vibrational interactions on surfaces. Applications include nanophysics, nanochemistry and photonics.
KEY-WORDS : surface microscopy; pulse electron source ; Rydberg atoms
- INTRODUCTION:...
Using pulsed optical-optical double resonance fluorescence depletion spectroscopy, many ro-vibrations of the NaH D$^1\Sigma$ state have been observed. The ab initio calculations show that the adiabatic potential energy curve of the NaH D$^1\Sigma$ state has a very shallow double-well structure, with completely different well widths giving different rotational constants and vibration spacing,...
We use the mathematical toolbox of the inverse scattering transform to study quantitatively the number of solitons in far from equilibrium one-dimensional systems described by the defocusing nonlinear Schrodinger equation. We present a simple method to identify the discrete eigenvalues in the Lax spectrum and provide a extensive benchmark of its efficiency. Our method can be applied in...
In the past decade, Rydberg atoms have emerged as promising and valuable tools for a myriad of quantum applications, and particularly quantum sensors. The exaggerated properties of Rydberg atoms make them highly sensitive to electric fields spanning from DC to THz frequencies, which makes them an appealing tool for sensitive, accurate, and simple sensors. This field is of tremendous interest...
Geometric magnetism addresses the geometric origin of enantio-sensitive observables in one or multiphoton ionization from the emergence of the propensity field $\vec{B}_{\vec{k}}$ [1]. We extend this approach to spin-resolved one-photon ionization, i.e., $\vec{B}_{\vec{k},\mu}=i\vec{D}_{\vec{k},\mu}^*\times\vec{D}_{\vec{k},\mu}$, where $\vec{D}_{\vec{k},\mu}$ is the spin-resolved transition...
Molecular ions offer more degrees of freedom than atomic ions. These larger Hilbert spaces are rich and interesting landscapes to explore, possibly enabling quantum information applications such as quantum error correcting (QEC) schemes not available in atomic ions. This requires efficient and precise control of the molecular ion states. Co-trapping a molecular ion with an atomic ion...
The relentless pursuit of higher precision in optical lattice clocks (OLC) demands ever more refined methods to mitigate environmental perturbations, with blackbody radiation (BBR) induced frequency shifts standing as a major challenge. State-of-the-art OLCs address this effect by either operating in a cryogenic environment to reduce the BBR [1], by employing comprehensive temperature...
Dissipative quantum many-body problems, such as those arising in collective light-matter interactions, present theoretical challenges. To explore these phenomena experimentally, we have developed an experimental setup that studies collective light scattering from an ordered ensemble of atoms. Recently, we achieved the first trapping and imaging of single dysprosium atoms in optical tweezers...
We report the results of theoretical studies for the dependence of collisional shift and width on isotopic mass in a Hg 1S0-3P0 clock transition perturbed by Rb atoms.
Our theoretical analysis uncovers isotopic dependencies over a temperature range from µK to K, highlighting specific isotope pairs with minimal collisional effects, making them well-suited for two-species Rb-Hg composite atomic...
Cavity-ringdown spectroscopy (CRDS) has become a cornerstone of modern spectroscopic techniques, known for its exceptional sensitivity and unique characteristics, such as calibration-free operation and immunity to light intensity fluctuations. These qualities result in highly accurate measurements of weak absorption lines. However, current continuous-wave (cw) laser-based methods require...
Optical vortices are optical beams characterized by a helical phase structure around their axis, possessing unique properties associated with orbital angular momentum (OAM) and phase singularities. Their significance is growing in both quantum communication and quantum computation due to their ability to encode and process information in higher-dimensional state spaces, expanding beyond...
The creation of ultracold heteronuclear molecules by assembly from precooled atoms has led to the realization of molecular gases with electric dipole-dipole interactions in the quantum degenerate regime [1,2], with exciting possibilities in the study of many-body dynamics, quantum computation and quantum simulation. One bialkali molecule that has yet to be realized in the ultracold regime is...
Nanoparticle (NP) mass spectrometry in the gas phase is a unique way
to characterize individual isolated particles and thus assess their
intrinsic properties, NP-to-NP variability and structural evolution,
e.g. in studies on charging mechanisms [1], photophysics [2] or high
temperature reaction kinetics [3]. Our group focuses on cryogenic
experiments to employ absorption spectroscopy,...
We investigate dilute Bose-Bose mixtures confined in an external harmonic potential that squeezes them in one spatial direction towards the two-dimensional limit, extending a recent study by some of the co-authors [1] by investigating rotating droplets which host vortices.
Specifically, we examine a quantum droplet composed of two hyperfine states of 39K potassium atoms, utilizing...
Nanoparticles have emerged as a promising platform for performing macroscopic quantum experiments and probing the quantum-classical boundary. Recent advances in the field include the motional ground state cooling of gigadalton (GDa) mass silica nanoparticles [1] and the demonstration of matter-wave interferometry with >25 kDa molecules [2]. We aim to trap, image and cool nanoparticles in the...
Ultracold quantum-gas mixtures of fermionic atoms with resonant control of interactions offer a unique test-bed to explore few- and many-body quantum states with unconventional properties. The emergence of such strongly correlated systems, as for instance symmetry-broken superfluids, is usually accompanied by hydrodynamic collective behavior. Thus, experimental progress in this field naturally...
Several negative molecular ions have been detected in the interstellar medium CN-, C3N-, C5N-, C7N-, C4H-,C6H-,C8H-,C10H-. Since their discovery, for many years, there had been a general consensus in the community of modelers that in the interstellar medium (ISM) the ions are formed by the process of radiative electron attachment (REA). However, in several recent studies it has been shown that...
Slow highly charged ions (HCIs) exhibit interesting phenomena when interacting with a solid. For example, a single ion can induce nanometer-sized deformations on a surface [1] and lead to the emission of more than 100 electrons [2]. These effects result from the ion’s large potential energy, ranging from tens to hundreds of keV [3], which is released within femtoseconds [4] upon impact....
Since the first pioneering experiments on signatures of superconductivity in laser-field driven materials [1], dynamical condensation effects have attracted a lot of experimental and theoretical interest. We theoretically study a related effect, i.e. fermionic condensation, in the paradigmatic Fermi-Hubbard model. Starting from a completely uncorrelated initial state, we show that upon...
The ionization of the water molecule by electron and positron impact has been theoretically studied through calculations of the triple differential cross section (TDCS) at low and intermediate impact energies. The Molecular Three Coulomb Wave with Variable Charge (M3CWZ) model is employed, where the incident, scattered, and ejected particles are described using Coulomb waves with a variable...
Liquid microjet is a technique which enables bringing volatile liquids into the vacuum. It has been developed for the purpose of photoelectron spectroscopy which remains its most frequent use in laboratories world-wide. We have recently adapted this technique for probing collisions of free electrons with liquid interfaces.
I will present two main research directions on the electron...
Compton scattering is the fundamental light-matter interaction process discussed in the textbooks as a billiard-type collision, in which a photon (as a particle) is deflected and transfers parts of its energy and momentum to an electron initially at rest. If electron is bound in an atom or molecule, its momentum distribution contributes to the balance, which is known as the impulse...
Ionization of molecules by electron impact represents one of the most fundamental interactions in nature, whose interest is relevant to a wide range of applications. Kinematically complete (e,2e) experiments, in which the energies and momenta of all final-state particles are determined, provide the most detailed information on the ionization reaction through the triple differential...
To access the natural timescale of electronic motion in molecules, attosecond resolution is needed. But triggering such ultrafast dynamics in excited molecules requires UV/Vis ultrashort pulses, of just a few femtoseconds. These pulses, that are becoming increasingly available in recent years [1], have a broad energy bandwidth, which creates a superposition of electronic excited states,...
The study investigates the execution of independent electrical control over two quantum dot emitters within the single photonic crystal microcavities along with coupled cavities as photonic molecule. We accomplish spatial separation of two quantum dots by splitting the cavity by inducing ion beam implantation, which allows for independent tuning without cross-interference. For photonic...
Supersolids are a remarkable state of matter, exhibiting both superfluidity and crystalline properties. We predict a rich excitation spectrum for a binary dipolar supersolid in a linear crystal geometry, where the ground state consists of two partially immiscible components forming alternating, interlocking domains. We identify three Goldstone branches, each exhibiting first-sound,...
Recent advances in attoscience have revealed that electron cloud dynamics, driven by superpositions of electronic states, can influence nuclear motion and, in turn, chemical reactivity [1]. In excited-state processes, conical intersections (CIs) play a central role and are both sensitive to and capable of generating electronic coherences—superpositions where overlapping electronic states...
Using the electron-ion crossed-beams technique, we have measured absolute cross sections for electron-impact single ionization of Xe$^{12+}$ and Xe$^{13+}$ ions, and double ionization of Xe$^{12+}$, Xe$^{13+}$, and Xe$^{14+}$ ions. In addition we have performed corresponding calculations using a hybrid level-to-level and subconfiguration-average distorted wave approach. We find excellent...
Three-body association describes the process where three atoms or molecules collide to form a bound complex between two of them. This process plays a role in a multitude of physical systems, for example ozone formation in the atmosphere, the formation of clusters in supersonic jets, cold and ultracold chemistry and in tagging spectroscopy [1]. Ab initio calculations of three-body association...
Heat engines convert thermal energy into mechanical work and have been extensively studied in the classical and quantum regimes. In the quantum domain, however, nonclassical forms of energy exist, which are distinct from traditional heat and which can also be harnessed to generate work in cyclic engine protocols.
We introduce the concept of the Pauli engine: a novel quantum many-body...
Phononic excitations in a Bose-Einstein condensate (BEC) exhibit dispersion relations analogous to those of relativistic scalar fields. It has been demonstrated that these fluctuations can be engineered to serve as quantum simulators for Friedmann–Lemaître–Robertson–Walker (FLRW) cosmologies [1]. We propose utilizing a BEC with long-range interactions induced by an optical cavity as a platform...
In recent years, a growing interest towards open-shell heteronuclear molecules can be noticed. These molecules attract particular attention of physicists involved in experiments at ultracold conditions, because they are known as "doubly polar molecules" having both electric and magnetic permanent dipole moments. Such properties provide a unique possibility for quantum control and...
This study explores the effect of heat treatment and helium (He) bubbles on the structure of SiC and the migration behaviour of silver (Ag) in SiC. Ag ions were implanted into polycrystalline SiC samples (Ag-SiC) at 350 °C and co-implanted with He ions at 350 °C (Ag + He-SiC). The samples were then annealed sequentially from 1000 °C to 1200 °C in steps of 100 °C for 5 hours. The implanted and...
Miniaturized atomic vapor cells of nanometric thickness have become promising platforms for fundamental measurements, metrology and quantum technologies. For example, nanometric cells have been used for exploring Dicke-type effects of confinement [1], measuring Casimir-Polder interactions, fabricating compact atomic clocks and probing collective effects. Extending these experiments to...
Precise individual addressing of single atoms in quantum registers formed by optical dipole trap arrays is essential to achieve high-fidelity quantum gates in neutral-atom quantum computers and simulators. Two-qubit quantum gates are typically realized using coherent two-photon laser excitation of atoms to strongly interacting Rydberg states [1]. However, two-photon excitation encounters...
Highly oriented pyrolytic graphite (HOPG) structural changes caused by gallium (Ga) implantation at room temperature were investigated. Raman spectroscopy was used to investigate the structural changes in HOPG after Ga implantation at different energies (i.e., 10, 20 and 30 keV) and fluences (i.e., 2×1015, 5×1015, 1×1016, 2×1016, 4×1016, 5×1016 cm-2). SRIM (Stopping and Range of Ions in Matter...
Molecules that are internally highly excited play an important role in a range of fields from atmospheric to plasma physics. Modelling such environments requires a detailed understanding of the molecules' behaviour at very strong excitations. However, this is a non-trivial task due to the high density of excited states as well as the variety of competing decay mechanisms available. The...
Hydrogen atom diffraction through free-standing single-layer graphene
Pierre Guichard,$^1$ Arnaud Dochain,$^2$ Raphaël Marion,$^{2,3}$ Pauline de Crombrugghe de Picquendaele,$^2$ Nicolas Lejeune,$^{2,4}$ Benoît Hackens,$^2$ Paul-Antoine Hervieux,$^1$ and Xavier Urbain $^2$
$^1$ Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, 67000...
Understanding internal dynamics and decay processes is crucial in gas-phase molecular anion studies. Using our lab’s unique facility[1], we investigated the long-timescale energy dynamics of Ag$_2^-$ and Cu$_2^-$ dimer anions. Internally hot anions from a Cesium sputter source are accelerated to 4.2 keV and stored in an Electrostatic Ion Beam Trap (EIBT). A laser-assisted velocity map imaging...
A dimer system can undergo ultrafast symmetry breaking by charge localization upon ionization. Our recent work explored symmetry braking dynamics in the Van der Waals bound $CO_2$ dimer using EUV pump - EUV probe Coulomb explosion imaging.[1] Here, I will present the symmetry breaking dynamics of a prototypical hydrogen bounded formic acid $(FA)$ dimer. Similar to DNA base pairs, the $FA$...
In recent years, ultracold molecules have become a very promising platform for quantum information processing, studying quantum many-body physics and testing new physics beyond the Standard Model of particle physics.
Similar to alkaline earth (like) atoms (Yb, Sr, Cd) aluminium monofluoride (AlF), has a strong dipole-allowed transition (near 227.5 nm) to capture and cool a large number of...
Positron interactions with atoms and molecules are characterised by strong many-body correlations including polarisation of the electron cloud by the positron, screening of the electron-positron Coulomb interaction, and the process of virtual-positronium formation (in which a molecular electron temporarily tunnels to the positron) [1]. The correlations significantly enhance annihilation rates,...
Ultracold atomic cloud is one of highly sensitive tools to search for undiscovered field as a quantum sensor in the vicinity of a surface [1, 2]. We have investigated interactions between ultracold atoms and a dielectric surface by an atomic fountain technique with moving an optical dipole trap beam. We initially loaded pre-cooled rubidium atoms to an optical dipole trap [3], and transported...
The study of the interactions between ion beams and biomolecules such as nucleobases, nucleosides, amino acids or peptides is a relevant topic for hadrontherapy applications. After interaction with the energetic ions, the biomolecular target could be ionized and excited. Molecular fragmentation is one of the relaxation process for such ionized/excited states. To better quantify the...
The standard model predicts a value for the electron’s electric dipole moment (eEDM, de), de ~ 10^-35 e cm [1], far smaller than what is predicted by theories beyond the standard model, typically de ≈ 10^-31 – 10^-24 e cm. To date, the current experimental upper limit is set at de < 4.1 x 10^-30 e cm [2]. Further improvements in experimental precision are likely to discover new physics or rule...
The three-dimensional momentum distribution of photoelectrons is determined by conservation laws embodied in the selection rules and depends on the state of the ionising light fields. The process of high harmonic generation, allows for the creation of light pulses of attosecond duration [1, 2], and the measurement of photoelectron momentum distributions following from the interaction with...
Over the past forty years, the CRESU (Cinétique de Réaction en Écoulement Supersonique Uniforme) technique has been a workhorse for investigating ion-molecule and neutral-neutral reactions in the low temperature regime [1], with temperatures reaching as low as 5.8 K [2]. The uniform supersonic flow, produced by a Laval nozzle, is known to be a wall-less, high-density flow of gas thermalised...
We present a new approach to model sequential ionization processes, employing a series of R-matrix with time-dependence (RMT) calculations to model the behaviour of the residual ion stages, and a density matrix to describe the coherences between the residual ion states. This combination allows us to describe correlated dynamics through multiple ionization stages.
RMT is a technique that can...
Terahertz (THz, 0.1-10 THz) precision spectroscopy of various molecular species is essential for several applications such as astrophysics and planetary atmosphere sensing, molecular physics, and tests of fundamental physics, yet it remains technically challenging. Such measurements require on one side the development of a dedicated spectrometer allowing for broadband measurements at...
Electron and ion beams have become indispensable tools in surface and material sciences, with an ever-increasing demand for higher resolution. This project aims to develop a Focused Ion Beam (FIB), called FIBback, leveraging two innovative concepts:
• A correlated source of ions and electrons, enabling, among other applications, complete trajectory control of the ion using information from...
All elements from rhenium to platinum will be produced in Tokamaks through neutron-induced transmutation of the tungsten which composed the divertor walls. Therefore, ionic impurities of all possible charge states should appear in the fusion plasma contributing to the power loss which does not make easy to get the self-maintained fusion reactions. However, the radiation emitted by these...
Optical lattice operating at the magic wavelength induces identical AC-Stark shifts on two internal states of trapped atoms, permitting a coherent control of the transition. The characteristics is vital for quantum applications based on cooled neutral atoms, including quantum computing, atom clock and precision metrology.
We discovered a new magic wavelength at 476.823545(55) nm for...
Recent advancements in spectroscopic techniques have enabled sub-MHz (1 MHz $\approx 3.3\cdot10^{-5}$ cm$^{-1}$) accuracy for selected rovibrational transitions in H$_2$ and its isotopologues [1-3]. This new level of precision has revealed minor yet significant discrepancies between measurements and theoretical predictions, presenting a new and severe challenge for theoretical models.
To...
Bose–Einstein condensates (BECs) provide a unique platform for studying quantum fluid dynamics, where macroscopic quantum phenomena such as superfluidity and quantised vortices emerge. Vortices in BECs are characterised by phase singularities in the condensate wave function, and they reveal insights into angular momentum quantisation and topological defects in quantum systems [1]. The study of...
The generation of ultra-stable microwave signals with low phase noise is a fundamental requirement for high-precision atomic clocks. In particular, state-of-the-art microwave fountains, such as those based on cesium (Cs) and rubidium (Rb) atoms, operate at the quantum projection noise (QPN) limit, where the stability of the interrogation signal plays a critical role. At LNE-OP, we have...
Using donut laser beams for atom trapping has the great advantage to reduce the residual absorption of the atoms and then the residual heating. Such traps allow to keep the atoms for a long time, which is important for many applications like Bose-Einstein condensation, or quantum simulation.
For such traps, blue-detuned single-ring Laguerre-Gaussian (LG) modes have been a lot experienced for...
The photonic orbital angular momentum (OAM) carried by an optical vortex (OV) is one of quantum variables relevant for quantum physics and photon entanglement [1,2].
Because OAM can take all signed integer values, they provide a wide basis for encoding and open many possibilities for entanglement. This is an advantage compared to the spin angular momentum.
In the other hand, the processes...
Photon scattering cross sections have proved essential in many applications, such as modelling opacities and radiative transport, studying the cooling of astrophysical plasma, analysing planetary atmospheres, and Raman spectroscopy.
In particular, Raman spectroscopy of H$_{2}$ plays an important in analysing hydrogen storage techniques, monitoring ortho-to-para conversion, and monitoring...
We are developing digital and analog quantum processors based on Cs neutral atom arrays. We plan to realize defect-free atomic arrays with more than 200 qubits. The atom array is expected to have state-of-the-art performance such as >1s qubit coherence time, >95% SPAM fidelity, > 99.9% and > 99% single and two qubit gate fidelity, respectively. Currently we have made some progress in system...
Cold negative ions offer promising applications in areas such as quantum information science, fundamental physics, and chemistry. However, the cooling of these ions to temperatures near the Doppler limit has not yet been achieved.
Beyond ongoing work on the cooling of C$_2^-$, the boron nitride anion (BN$^-$) has emerged as a possible candidate ion for optical cycling and Doppler laser...
The rotation of trapped molecules, with state spaces of larger angular momentum and their relatively large electric dipole moments, could offer a promising platform for quantum technologies and quantum information processing (QIP). To explore the experimental utility of molecules for various quantum applications, we are developing state preparation and coherent control protocols based on...
Virtual excitations, inherent to ultrastrongly coupled light-matter systems, induce measurable modifications in system properties, offering a novel resource for quantum technologies. In this work, we demonstrate how these virtual excitations and their correlations can be harnessed to enhance precision measurements, without the need to extract them. Building on the paradigmatic Dicke model,...
Recently, it was found that the positronic complex with (H−)2 can form the stable bound state concerning the dissociation into H− + PsH by a positron mediate bonding. This bonding situation, which resembles the well-defined single covalent bond, was qualified as “positronic covalent bonding”. On the other hand, a similar binding mechanism may be possible for anion dimers of other alkali...
We predict that ultracold bosonic dipolar gases, confined within a multilayer geometry, may undergo self-assembling processes, leading to the formation of chain gases and solids. These dipolar chains, with dipoles aligned across different layers, emerge at low densities and resemble phases observed in liquid crystals, such as nematic and smectic phases. We calculate the phase diagram using...
Radiation damage on genetic materials is very important field of research. Photoionization studies of small biomolecular building blocks and their analogues can contribute by giving insights into energetics and dynamics of pathways of formation of secondary electrons and cationic dissociation reactions. Here, I present double imaging photoelectron photoion coincidence study of pyridine,...
Creating arrays of ultracold molecules for quantum simulation of many-body systems is rapidly becoming a reality [1,2]. A key requirement for high-fidelity simulation of various spin models is the ability to simultaneously recover the population in each spin state. Using a series of manipulations proposed in [3], we experimentally demonstrate that two rotational states of ultracold RbCs...
Light can be used to modify and control properties of quantum systems in many areas of physics. The excitation and ionization of atoms and molecules are at the heart of strong-field physics and ultrafast nonlinear optics, playing a central role in various phenomena such as light-induced electron diffraction (LIED), high harmonic generation (HHG) and spectroscopy (HHS), atomic stabilization in...
Photodetachment spectroscopy is a powerful spectroscopic technique for determining the internal state distribution of a molecular anion. Previously, our group studied the threshold photodetachment spectroscopy of CN$^-$ at both 16 K and 295 K in a 22-pole ion trap and measured the electron affinity of CN with great precision (EA: 3.864(2) eV) [1]. Here, we present results from our recent study...
Precision gravitational wave measurement transforms research beyond general relativity and cosmology. Advances are made by applying quantum enhanced interferometry into the LIGO, Virgo and KAGRA detectors. Here, we develop an atomic sensor that employs a p-orbital Bose-Einstein condensate in an optical lattice to project gravitational wave signals into an orbital squeezed state. This entangled...
Atom interferometers are reaching sensitivities fundamentally constrained by quantum fluctuations [1]. A main challenge is to integrate entanglement into quantum sensing protocols to enhance precision while ensuring robustness against noise and systematics [2-4]. Here, we theoretically investigate differential phase measurements with two atom interferometers using spin-squeezed states [5],...
The neutral alkali beams, such as lithium and sodium, were shown to be invaluable for measuring turbulence and electron density profiles in the boundary plasma [1]. These beams have also been proven to be useful for measuring local impurity properties using charge-exchange recombination spectroscopy [2]. The cross section calculations are vital to determine which spectral line can be...
An association reaction of H$_3^+$ ions with H$_2$ forming H$_5^+$ was studied in the temperature range of 15 – 35 K with either helium or hydrogen acting as a third body to understand the role of rotational excitation of colliding bodies.
A 22-pole radio-frequency ion trap apparatus [1] was employed to study the influence of the internal excitation of the reactants on the measured ternary...
The configuration space, i.e. the Hilbert space, of compound quantum systems grows exponentially with the number of its subsystems: its dimensionality is given by the product of the dimensions of its constituents. Therefore a full quantum treatment, in general, is hardly possible analytically and can be carried out numerically for fairly small systems only. Yet, in order to obtain interesting...
TMPyP4 is well-known meso-substituted porphyrin with high biological activity and unique spectroscopic and photophysical properties. This highly symmetric (D2h) fluorescent compound is widely used as a photosensitizer in anticancer PDT, anti-viral and antimicrobial agent, an efficient probe for the nucleic acids structure and dynamics, a carrier of antisense oligonucleotides for their...
The HyperMu experiment at PSI aims at the first measurement of the ground state hyperfine splitting in muonic hydrogen (μp) with 1 ppm precision using pulsed laser spectroscopy. This accuracy allows for a precise extraction of the proton structure contributions, including the Zemach radius and the proton polarizability.
To measure the ground state hyperfine splitting in μp, we are...
Molecular compounds based on boron-dipyrromethene (BODIPY) have been shown to be promising candidates for microscopic, single-molecule scale sensing of environment properties, such as temperature or viscosity [1]. It is also possible to anchor the sensors to a specific type of microscopic environment, e.g. a lipid cell membrane, where the restricted molecular drift results in a measurable...
Ultracold quantum gases offer a highly tunable platform for exploring strongly interacting many-body systems. In highly imbalanced mixtures, we can explore the quantum behavior of impurities. Our investigation focuses on bosonic $^{41}$K impurities interacting with a Fermi sea of $^6$Li atoms, forming a system that can be described in terms of quasiparticles known as Fermi polarons. While...
The feasibility of performing merged beam experiments with trapped fast ion beams of molecular cations and anions at the double electrostatic storage ring (DESIREE) and the hybrid electrostatic ion beam trap (HEIBT),[1,2] opens new opportunities to study mutual neutralization reactions. Here, I will present our findings from merged beam experiments performed at DESIREE on the mutual...
We present experimental results on the solvation dynamics of a single alkali cation in liquid helium, measured with atomic resolution and with femtosecond time resolution [1-2].
A single Na, K or Li atom sitting in its equilibrium position on the surface of a He nanodroplet is ionized by a 50 fs laser pulse. Thereby, an alkali ion, Ak$^+$, is introduced instantly to the liquid helium...
Quantum logic spectroscopy enables high-precision studies of molecular ions by using the controllability of co-trapped atomic ions. Molecular ions possess complex rovibrational structures that are challenging to probe directly. Instead, they can be sympathetically cooled and manipulated using atomic ions, allowing indirect measurements through shared motion in a trap. We present an...
We are designing a setup composed of a hollow hemispherical mirror, an active boundary condition and a trapped ion for application in quantum networks. The ion will be held in the focal point of the system so that its spontaneous emission will be controlled both by the hemispherical mirror and by the active boundary condition. The hemispherical mirror will suppress the emission at high angles,...
Chirality is a fundamental geometric property, present from molecular to macroscopic scales. Traditional chiroptical methods rely on weak magnetic interactions, limiting their efficiency. We aim to develop chiral recognition methods based solely on electric-dipole interactions, offering enhanced enantiosensitivity [1].
We investigate the carrier-envelope phase (CEP) dependence of...
In this research, we design and experimentally implement various robust quantum unitary transformations (gates) acting on d-dimensional vectors (qudits) by tuning a single control parameter using optimal control theory. The quantum state is represented by the momentum components of a Bose-Einstein condensate (BEC) placed in an optical lattice, with the lattice position varying over a fixed...
Collisions between charged and neutral particles play a central role in atomic and molecular physics. A significant area of investigation lies in the study of electron and positron impact single ionization of atomic and molecular targets, known as (e,2e) processes, which shed light on the behavior of electrons and positrons during their interaction with the target in the entry channel, as well...
