Laser spectroscopy of muonic atoms, hydrogen-like atoms formed by a negative muon and a nucleus, has recently provided the charge radii of the lightest nuclei (proton, deuteron, 3He and 4He) with unprecedented accuracy. In this talk we present laser spectroscopy of these exotic atoms and their contribution to nuclear physics. Emphasis will be given to the new results in 3He.
Moreover we...
Precision atomic spectroscopy provides a solid model independent bound on
the existence of new dark forces among the atomic constituents. We focus on the keV-GeV region investigating the sensitivity to such dark sectors of the recent measurements on muonic atoms at PSI, muonium and positronium. To this end we develop for the first time, the effective field theory that describes the leading...
Due to its lack of internal structure, Muonium is an excellent candidate to provide stringent tests for bound state QED. Furthermore, Muonium is a sensitive probe for the existence of exotic dark-sector particles, new muonic forces, and hidden dimensions. During the Mu-MASS [1] beamtime in December 2019 at the LEM beamline at PSI, we demonstrated the creation of an intense directed beam of...
The next-generation neutron electron dipole moment (EDM) measurement is currently under construction at the Paul Scherrer Institute (PSI), the n2EDM experiment. n2EDM will deliver, at minimum, an order of magnitude better sensitivity as compared to current limits on the neutron EDM. This increased sensitivity on the neutron EDM will provide stringent constraints on time-reversal violating...
At the Paul Scherrer Institute we are developing a high precision instrument to measure the electric dipole moment (EDM) of the muon. The presence of a permanent EDM in an elementary particle would imply a violation of time invariance and the combined symmetry of Charge-Parity (CP). While the Standard Model of particle physics allows for a large CP-violating phase, it also predicts EDMs that...
The LEMING (LEptons in Muonium INteracting with Gravity) experiment aims to measure the gravitational acceleration of Muonium (M = e$^−$ + μ$^+$ ) in the gravitational field of the earth. An essential part of this experiment is the reliable detection of M’s decay products, i.e. e$^+$ and e$^−$, at temperatures below 1$\,$K. The electron, referred to as atomic electron, can be accelerated to...
We present a recent progress towards experiments with hydrogen atoms at ultra-low temperatures, probing the ultra-low energy domain with the lightest and simplest of neutral atoms, which has served as a test probe of the fundamentals of physics throughout the era of modern physics. This work is a part of an international collaboration GRASIAN (Gravity, Spectroscopy and Interferometry with...
The upgrade of the antiproton decelerator, the Extra Low ENergy Antiproton (ELENA) ring started its operation at CERN in the Fall of 2021 and opened a new era for antihydrogen research. The Gravitational Behaviour of Antihydrogen at Rest (GBAR) collaboration has since started taking data and aims to directly test the Weak Equivalence Principle with a free fall of ultracold antihydrogen...
Low-energy properties of the nuclei can be precisely examined via highly accurate measurements of atomic transitions. As the Bohr radius of hydrogen-like atoms decreases with increasing orbiting particle mass, the muonic atoms (hydrogen-like atoms formed by a negative muon and a nucleus) have enhanced sensitivity to nuclear structure effects. The HyperMu experiment is motivated to measure this...
The muCool project aims to develop an innovative device for generating low-energy, high-intensity, and high-quality muon beams for future high-precision experiments such as muon g-2 measurements, muonium spectroscopy, and muonium gravity studies. These experiments, involving muons and muonium atoms, hold significant potential for testing theoretical predictions of the Standard Model within a...
Muonium, the purely leptonic bound state of an anti-muon and an electron, is an excellent candidate to probe bound state QED and search for new physics beyond the Standard Model.
I will introduce Mu-MASS, aiming to improve the Muonium 1S-2S transition and Lamb Shift by orders of magnitude. I will present our latest experimental progress and results, with a special focus on the New Physics...
The Baryon Antibaryon Symmetry Experiment (BASE) at the antiproton decelerator of CERN is dedicated to high-precision measurements of the fundamental properties of the proton and the antiproton. Using single-particle multi-Penning-trap techniques, we compare the proton/antiproton charge-to-mass ratios [1] and magnetic moments [2,3] at a relative uncertainty at the 10-parts-per-trillion and...
The LUXE experiment at the DESY in Hamburg (DE) will study strong-field quantum electrodynamics in the interactions of a beam of electrons or photons with a high-intensity laser. New electrons, positrons, and photons can be created in Compton and Breit-Wheeler processes. The main objective of LUXE is to measure the laser intensity dependence of the matter-antimatter pair production rate....
The energy levels of hydrogen-like systems can be both calculated and measured very precisely. Precision spectroscopy of two transitions at the current level of accuracy allows the determination of the Rydberg constant and the proton charge radius. Comparison with an additional transitions can serve as a consistency check for the theory of quantum electrodynamics. The recent discrepancy in...
Using an atom interferometer, it is possible to precisely measure the ratio between the Planck constant and the mass of an atom. This measurement allows improving the determination of the fine structure constant α. By using this value in the QED prediction of the magnetic moment of the electron, it is possible to precisely test the Standard Model. This test is particularly relevant as it is...
The Standard Model of particle physics perfectly describes most of the observed phenomena, but leaves a number of problems unresolved, including the origin of the matter-antimatter asymmetry, the nature of dark matter, the absence of observed CP violation in the strong sector, the fine tuning needed for light Higgs. Most extensions of the Standard Model involve the introduction of new...
In this talk, I present a novel approach based on precision laser interferometry that combines the search for axion-like particles and low-mass scalar-field dark matter with the investigation of quantum space-time fluctuations. For the dark matter search, our method employs polarimetry with a Fabry-Perot cavity in combination with high birefringence crystals to achieve unprecedented...
In this talk, I will introduce AION, a multi-stage atom interferometer project that aims to detect ultra-light dark matter candidates. The first stage, AION-10, will stand 10m tall in a stairwell in the Physics Department in the University of Oxford. AION-10 will operate in a gradiometer configuration, which means that two identical atom interferometers are run simultaneously, launching from...
Spectroscopy of the HD$^+$ molecular ion has made a ''quantum'' leap in recent years, reaching part-per-trillion precision by use of techniques for Doppler-free excitation. The theoretical precision has also been improved, both in the spin-averaged transition frequencies and in hyperfine structure.
Under the assumption that the Standard Model correctly describes the physics of HD$^+$,...
Recent advances in precise control and study of molecules have opened up new opportunities for fundamental physics research. Radioactive molecules, in particular, can be artificially created to contain nuclei with extreme proton-to-neutron ratios, providing an extreme sensitivity to symmetry-violating nuclear properties. Precision measurements of these systems can offer unique and...
The complexity and variety of molecules offer promising applications in metrology and quantum information that go beyond what is possible with atomic systems. We aim to study light molecular ions that are amongst the most fundamental and simplest molecules. Their internal structure can be calculated, making them prime candidates for the determination of fundamental constants as well as for...
The Jaynes-Cummings model describes the system of a two-level atom which is interacting with a photon field in a quantum-mechanical framework. We present a Rabi-type experiment that tests this model. Our system comprises the nuclear spin of protons in water and an oscillating magnetic field. We measured the spin-state transition with various numbers of electromagnetic-field quanta involved.
At very low energies, a light neutral particle above a horizontal surface can experience quantum reflection. The quantum reflection holds the particle against gravity and leads to gravitational quantum states (GQS). So far, GQS were only observed with neutrons as pioneered by Nesvizhevsky and his collaborators at ILL. However, the existence of GQS is predicted also for atoms.
The...
In the ALPHA Experiment, laser-cooling of beryllium ions has been introduced to sympathetically cool positrons [1], which is anticipated to increase antihydrogen production [2]. Beryllium ions are generated through Pulsed Laser Ablation [3] and are trapped in the same Penning-Malmberg trap utilized for trapping and preparing antiproton and positron plasmas for antihydrogen synthesis. Cold...
Muonium ($M = \mu^+ + e^-$) is a purely leptonic exotic atom which can be used as an unique probe for New Physics through precision spectroscopy measurements or through a gravity measurement testing the weak equivalence principle on elementary antimatter. We are developing a novel M source based on stopping accelerator muons in a layer of superfluid helium at cryogenic temperatures.
In this...
We present a novel technique for in-vacuum cavity-enhanced UV spectroscopy that allows nearly continuous measurements over several days, minimizing mirror degradation caused by high-power UV radiation. Our method relies on pulsing of the cavity's internal power, which increases the UV intensity to maximum only for short periods when the studied atom is within the cavity mode volume while...
I will describe work performed on a Paul trap where we have demonstrated splitting and merging of mixed-species ion chains containing beryllium and calcium ions. These have a large mass ratio of > 4, which presents a number of complications, including decoupling of motional modes and large differences in mode frequencies, which primarily result from the difference in pseudo potential...
Precision measurements of nuclear charge radii provide important inputs for modern nuclear theory, helping to improve our understanding of nuclear forces. The spectroscopy of muonic atoms is known as a highly precise method for such measurements. However, in the case of low- to medium-Z nuclei, the covered energy range has so far been difficult to access using laser spectroscopy or...
uonic helium is a hydrogen-like atom composed of a helium atom with one of its electrons replaced by a negative muon. Its ground-state hyperfine structure (HFS), resulting from the interaction of the remaining electron and the negative muon magnetic moment, is very similar to muonium but inverted. High-precision measurements of the muonium ground-state HFS interval are recognized as the most...
The complexity and variety of molecules offer promising applications in metrology and quantum information that go beyond what is possible with atomic systems. We aim to study light molecular ions that are amongst the most fundamental and simplest molecules. Their internal structure can be calculated, making them prime candidates for the determination of fundamental constants as well as for...
The exploration of dark matter beyond the standard lore is of vital importance towards resolving the identity of dark matter. I will discuss new proposals for the direct detection of light dark matter which hold much promise. These include the use of superconducting nanowires, two-dimensional targets such as graphene, and heavy fermion materials. Considering dark matter interactions with these...
Antiprotonic atoms have been produced since the 1980's, but recent developments of laser-controlled controlled charge exchange processes in Penning traps have opened up a wide range of new physics topics. This talk will address several of these, whose physics reach ranges from atomic cascades within antiprotonic Rydberg atoms, a new production method of trapped, cold, fully stripped...
The QUest for Axion (QUAX) is a direct-detection CDM axion search which reaches the sensitivity necessary for the detection of galactic QCD-axion in the range of frequency 8.5-11 GHz.
The QUAX collaboration is operating two haloscopes, located at Padova/LNL- and LNF-INFN laboratories in Italy, that work in synergy and operate in different mass ranges.
In this talk we will report about...
The search for a quantum theory of gravity has led to the discovery of quantum many-body systems that are dual to gravitational models with quantum properties. The perhaps most famous of these systems is the Sachdev--Ye--Kitaev (SYK) model. It features maximal scrambling of quantum information, and opens a potential inroad to experimentally investigating aspects of quantum gravity. A scalable...
Quantum gases coupled to high-finesse optical resonators are a versatile platform to simulate many-body quantum systems, offering a high degree of experimental control. All-to-all interactions between the atoms naturally arise in such systems from the coupling of the atoms to a cavity mode, while cavity leakage facilitates real-time access to the dynamics of this open quantum system.
Here, we...
The time evolution of an quantum system can be strongly affected by dissipation. Although this mainly implies that the system relaxes to a steady state, in some cases it can bring to the appearance of new phases and trigger emergent dynamics. In our experiment, we study a Bose- Einstein Condensate dispersively coupled to a high finesse resonator. The cavity is pumped via the atoms, such that...
A nanosphere levitated in electromagnetic fields is a promising testbed for physics at the interface between the classical and the quantum realm. Recently, levitated particles have attracted attention as potential gravity quantum sources due to their large mass, ranging from $10^9$ to $10^{12}$ amu. A prerequisite to test the quantization of the gravitation field is, however, to prepare the...
The neutron represents a versatile tool in the realm of fundamental particle physics. It is used to perform precision physics measurements at low energies with the goal to search for beyond Standard Model signals. In this presentation, we will introduce activities currently pursued at the University of Bern. The projects encompass the hunt for a CP-violating neutron electric dipole moment...
Precision measurements of $\beta-$decay spectra can provide exquisitely sensitive tests of various predictions and underlying symmetry assumptions of the Standard Model (SM) of Particle Physics. Hypothetical scalar- and tensor-type interactions can alter the shape of the $\beta-$decay spectrum across the full energy range, while the finite masses of neutrinos mostly alter its shape around the...
The extreme precision and accuracy of state-of-the-art optical atomic clocks can be used to look for very small deviations from the predictions of the Standard Model, offering a tool to search for beyond Standard Model (BSM) physics complementary to particle accelerators. These searches are based on measuring the frequency ratio of two transitions that depend differently on interactions with...
Experiments with single ions confined in a Penning trap enable access to a broad range of observables that are of fundamental importance for our understanding of fundamental physics. In the magnetic field of the trap, the cyclotron frequency of an ion can be determined with unique precision and gives direct access to the charge-to-mass ratio. Furthermore, we have access to the gyromagnetic...
I will present recent results of a search for new physics using isotope-shift spectroscopy of $\text{Yb}^+$ ions at MIT [1,2], and plans for IS spectroscopy experiments in $\text{Ca}^+$ at ETH Zurich. Recently, IS spectroscopy of atoms and ions has been proposed as a method to search for a new force between the neutron and the electron, mediated by a hypothetical dark-matter-candidate boson in...
Precision spectroscopy of the 1S-2S transition in singly-ionized hydrogen-like helium is a promising avenue to test bound-state quantum electrodynamics. Additionally, combined with measurements on $\mu$He$^+$ [1], nuclear size effects and the nuclear polarizability can be probed [2]. He$^+$ can be confined in a Paul trap and sympathetically cooled by laser-cooled Be$^+$, which also serves as...
I will discuss laser spectroscopy, particularly on the 1S-2S transition, of Hydrogen (H) and Antihydrogen (Hbar). The study of H recalls the work done at MIT in mid 90's and the setup under construction at UFRJ. The work with Hbar is done at the ALPHA collaboration at CERN. Details on line shapes, transition rates, detection schemes, will be discussed. The work has intimate connection to...
I will present the 1S-3S spectroscopy campaign we carried on Deuterium atoms during the winter 2020, using our home-made CW 205 nm laser. After discussing some main systematics effects and a newly discovered one, affecting our beam-line, I will present the latest analysis results.
The metastable He ((1s)$^1$(2s)$^1$) atom in its singlet ($^1$S$_0$) or triplet ($^3$S$_1$) states is an ideal system to perform tests of ab-initio calculations of two-electron systems that include quantum-electrodynamics and nuclear finite-size effects. The recent determination of the ionization energy of the metastable
$2\,^1$S$_0$ state of $^4$He [1] confirmed a discrepancy between the...
Despite decades of effort, quantum electrodynamics (QED), the field theory that describes the interaction between light and charged particles, is poorly tested in the regime of strong coulomb fields. This is due to a confluence of difficulties linked to experimental limitations in highly-charged ion spectroscopy and nuclear uncertainties. I will present a new paradigm for probing higher-order...
I would like to discuss the theory of light muonic atoms, in particular, the two-photon-exchange polarizability contributions to the Lamb shift and hyperfine splitting in muonic hydrogen from baryon chiral perturbation theory and the two-photon-exchange contribution to the Lamb shift in muonic deuterium from pionless effective field theory. A focus will be on the ground-state hyperfine...
Ultralight scalar dark matter may induce apparent oscillations of the fundamental constants of nature and particle masses, including the muon mass. Oscillations in the muon mass may be directly probed via temporal shifts in the spectra of muonium and muonic atoms. Existing datasets and ongoing spectroscopy measurements with muonium are capable of probing scalar-muon interactions that are up to...
P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow, Russia
Cold atoms have many applications in quantum sensors and quantum simulations. Most studies in this field are performed in the so-called cycle mode, where stages of experiment are performed sequentially. Due to the rapid progress in laser systems, funda- mentally different schemes with spatial separation and...
P.N. Lebedev Physical Institute of the Russian Academy of Sciences, Moscow, Russia
Optical clocks are one of the most precise instruments today with applications ranging from tests of fundamental physics to relativistic geodesy. The 1.14 μm clock transition in neutral thulium has exceptionally low sensitivity to the environment, including electric and magnetic fields and blackbody...
