We discuss recent advances towards matter-wave interference experiments with free beams of metallic and dielectric nanoparticles. They require a brilliant source, an efficient detection scheme and a coherent method to divide the de Broglie waves associated with these clusters: We describe an approach based on a magnetron sputtering source which ejects an intense cluster beam with a wide mass dispersion but a small velocity spread of Δv/v < 10%. The source is universal as it can be used with all conducting and many semiconducting or even insulating materials. Here we focus on metals and dielectrics with a low work function of the bulk and thus a low cluster ionization energy. This allows us to realize photoionization gratings as coherent matter-wave beam splitters and also to realize an efficient ionization detection scheme. These new methods are now combined in an upgraded Talbot-Lau interferometer with three 266 nm depletion gratings. We here describe the experimental boundary conditions and how to realize them in the lab. This next generation of near-field interferometers shall allow us to soon push the limits of matter-wave interference to masses up to 106 amu.
Since the early 20th century, molecular beam research has led to many advances in physics and chemistry, from precision molecule metrology, over tests of fundamental symmetries, and molecular quantum optics to applied mass spectrometry. All such experiments share a common interest in isolating molecules in high vacuum to eliminate any perturbing environment and to be able to probe the particle’s response to tailored optical, electrical or magnetic fields. Here we propose a scheme to explore the properties of charge-reduced or neutral biopolymers and ways to detect them without the need for post-ionization.
The wave-particle duality is a key concept of quantum physics and extending quantum superpositions to bodies of increasing mass and complexity has become a key goal to numerous research groups. Such experiments are motivated by the desire to probe and better understand the quantum-classical interface in advanced tests of spontaneous or gravity-induced wave function collapse and in the search for non-linear modifications of quantum theory. High mass interferometry has been proposed to serve in the search for light dark matter via weak recoil decoherence as well as in tests of the weak equivalence principle by comparing a large variety of quantum systems with very distinct internal composition, excitation, mass, shape or angular momentum.
Here we discuss the experimental state of the art in high-mass matter-wave interferometry, as well as new perspectives from cluster and nanoparticle physics to push quantum superpositions by 3 to 4 orders of magnitude in mass or up to 6 orders of magnitude in 'macroscopicity'. We discuss different near-field interferometer configurations that shall become useful in near-future demonstrations of quantum phenomena with objects as diverse as proteins, metal clusters and dielectric nanoparticles.
We review the concept of matter-wave assisted molecule metrology and present the most recent experiments which exploit the capability of universal matter-wave interferometers to measure forces as small as 10-26 N via shifts of the interference fringes in the presence of well-controlled fields. This technique allows us to compare, in the same instrument, a variety of electronic and magnetic properties for a large range of atoms and molecules. We exemplify this here with precision measurements of the static polarizability of cesium atoms and the fullerenes C60 and C70 as well as dynamically-induced susceptibilities of tailored tripeptides. We also present measurements of magnetic properties such as the diamagnetic susceptibility of ground-state atoms and aromatic and non-aromatic hydrocarbons.
Optomechanical systems, where the mechanical motion of objects is measured and controlled using light, have a huge range of applications, from the metre-scale mirrors of LIGO which detect gravitational waves, to micron scale superconducting systems that can transduce quantum signals. A fascinating addition to this field are free or levitated optomechanical systems, where the oscillator is not physically tethered. We study a variety of nanoparticles which are launched through vacuum (10−8 mbar) and interact with an optical cavity. The centre of mass motion of a nanoparticle can be cooled by the optical cavity field. It is predicted that the quantum ground state of motion can be reached, leaving the particle free to evolve after release from the light field, thus preparing nanoscale matter for quantum interference experiments.
We have designed a gravitational cavity for ultra-cold atoms using an atomic mirror made from an evanescent laser wave. By a temporal variation of the evanescent wave intensity, we have realized various atom optics components such as temporal slits and phase modulators. We have also designed an atom interferometer using this cavity which proves that the coherence of the de Broglie waves can be preserved during the bounce of the atoms on the mirror.
Paramagnetic impurities tapped in solid helium matrices are a new experimental sample with outstanding physical properties. One of the most challenging applications of paramagnetic atoms embedded in solid helium is the search for P- and T-violating permanent atomic electric dipole moments. Prerequisites for such an experiment are among others the achievement of a high degree of spin polarization by optical pumping, a long spin relaxation time and the efficient detection of electron spin magnetic resonance. In the present paper we present preliminary results along these lines. We also show that the technique of optically detected magnetic resonance is an efficient tool for the investigation of matrix effects due to anisotropies of the local trapping sites.
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