Ultra-cold atoms systems used as quantum simulators offer an alternative way to simulate many-body systemsbehaviour in condensed matter. Indeed, we can create artifcial matter with optical lattices : the stationnarywave reproduces the potential wells in the crystalline structure. Moreover, the big advantage of using coldatoms is that the parameters of the simulated crystal can be well controlled so that we can understand theelectrical and magnetism properties of the condensed matter such as conductivity, ferromagnetism ...Thecommon approach for generating optical lattices is interfering two laser beams in one dimension. And in the newongoing project, we are going to produce lattices by irradiating a nanostructure gold layer, which can realizesub-wavelength optical lattices due to the surface plasmon resonance and Casimir-Polder effects.
Ultra-cold atoms systems used as quantum simulators offer an alternative way to simulate many-body systemsbehaviour in condensed matter. Indeed, we can create artifcial matter with optical lattices : the stationnarywave reproduces the potential wells in the crystalline structure. Moreover, the big advantage of using coldatoms is that the parameters of the simulated crystal can be well controlled so that we can understand theelectrical and magnetism properties of the condensed matter such as conductivity, ferromagnetism ...Thecommon approach for generating optical lattices is interfering two laser beams in one dimension. And in the newongoing project, we are going to produce lattices by irradiating a nanostructure gold layer, which can realizesub-wavelength optical lattices due to the surface plasmon resonance and Casimir-Polder effects.
Ultra-cold atoms systems used as quantum simulators offer an alternative way to simulate many-body systemsbehaviour in condensed matter. Indeed, we can create artificial matter with optical lattices : the stationnarywave reproduces the potential wells in the crystalline structure. Moreover, the big advantage of using coldatoms is that the parameters of the simulated crystal can be well controlled so that we can understand theelectrical and magnetism properties of the condensed matter such as conductivity, ferromagnetism ...Thecommon approach for generating optical lattices is interfering two laser beams in one dimension. And in the newongoing project, we are going to produce lattices by irradiating a nanostructure gold layer, which can realizesub-wavelength optical lattices due to the surface plasmon resonance and Casimir-Polder effects.
Ultra-cold atoms systems used as quantum simulators offer an alternative way to simulate many-body systemsbehaviour in condensed matter. Indeed, we can create artificial matter with optical lattices : the stationnarywave reproduces the potential wells in the crystalline structure. Moreover, the big advantage of using cold atomsis that the parameters of the simulated crystal can be well controlled so that we can understand the electricaland magnetism properties of the condensed matter such as conductivity, ferromagnetism ...The commonapproach for generating optical lattices is interfering two laser beams in one dimension. The lattice spacing islimited by the interfringe, which is half the wavelength. However, the more the lattice spacing decreases, themore the interaction energies increase [3].In the new ongoing project, we are going to produce subwavelengthlattices by irradiating a nanostructure gold layer. The subwavelength potential is got thanks to the control ofthe interactions between the beams, the atomic cloud, and the nanostructured surface. This system will be ableto study new interaction regimes with very high tunability (different lattice geometries, impurities...).
The entry into the new millennium was marked in the quantum community by the first experimental realizations of the Bose-Einstein condensation of atoms in a vapor, achieved in different research groups. Twenty-five years later, such systems are 'routinely' produced and are the core of many experiments. At the frontier between condensed matter their y, quantum optics, and atomic physics, ultra-cold atoms are subjects of high scientific interest.Ultra-cold gas can be trapped in optical lattices, giving a realistic way of experimentally realizing a new range of lattice Hamiltonians, that are used to simulate condensed matter systems. In these simulations, ultra-cold atoms are used to mimic the behavior of electrons in a solid-state material and could be used to simulate a wide range of complex condensed matter phenomena, such as the fractional quantum Hall effect, topological insulators, and high-temperature superconductivity.In order to study such systems, diffraction-limited quantum gas microscopes have emerged as a way to manipulate and detect atoms trapped in lattice potentials. Using far-field interference, experiments have mainly been restricted to a lattice spacing of 500 nm. This limits the speed of dynamics of all physical processes.Higher energy regimes could be accessed by reducing the lattice spacing. For this purpose, one of the long-term goals of the team is to trap atoms in the near-field of a surface and to make use of the Casimir-Polder forces to shape sub-wavelength potentials. Thanks to nano-fabrication capabilities, the spacing can be reduced to a few tens of nanometers. However, this requires to adapt the imaging techniques to observe cold-atoms with sub-wavelength spatial resolutions.In this PhD thesis, I report first on the advances toward implementing an atom chip in our experiment, which will serve as an integrated platform to manipulate the quantum gas. I present simulations and study an experimental solution allowing the cloud to be transported to the near-field. The method is based on the interference of a laser radiation in the near field of a rotating surface. It has been fully simulated, and the limitations have been numerically and experimentally assessed. I conclude this part by presenting the first model of chip that has been fabricated.In a second part, I report on the development of a sub-wavelength imaging method of cold Rubidium 87 atoms which is based on excited state dressing. I detail the concept of this nano-metric spatial resolution method and apply it to super-resolve a single longitudinal wave function trapped in a tight lattice that exhibits a width below 30 nm.
In recent years ultracold atomic gases have emerged as a new and promising platform for exploring the physics of quantum many-body systems, allowing researchers to revisit fundamental problems of condensed-matter physics such as superconductivity or magnetism. By trapping ultracold atoms in the periodic potential created by interfering laser beams (a so-called optical lattice), it has indeed become possible to engineer very clean ?materials? whose parameters can be tuned in a wide range. This bottom-up approach comes very close to Feynman?s idea of a ?quantum simulator?, an
In recent years ultracold atomic gases have emerged as a new and promising platform for exploring the physics of quantum many-body systems, allowing researchers to revisit fundamental problems of condensed-matter physics such as superconductivity or magnetism. By trapping ultracold atoms in the periodic potential created by interfering laser beams (a so-called optical lattice), it has indeed become possible to engineer very clean ?materials? whose parameters can be tuned in a wide range. This bottom-up approach comes very close to Feynman?s idea of a ?quantum simulator?, an
Recently, cold atoms in lattices blossomed as good candidates to mimic the prop- erties of electrons in solid state systems and to simulate other quantum systems. However, experimental techniques currently use optical lattices in the far-field. This limit the lattice spacing to λ/2, thus the relevant energy scale (tunneling and interaction), making it difficult to enter deeply into the proper quantum regimes to observe magnetic quantum correlations or strongly correlated phases. Our project aims at reducing the lattice period to bridge the gap between solid state ( ̊A) and far field lattice (500nm) by developing an hybrid quantum system of Bose and Fermi quantum gas in close proximity of a nano-structured surface generating sub-wavelength lattice potentials. To push toward this goal, we first developed a novel method to transport and then trap an ultracold atomic cloud in close vicinity of a surface. We will discuss about the early stage atom-chip produced, and report on some tests about the transport sequence. By measuring the power spectral density of the trap parameters, we can predict the noise- induce heating of the trapped cloud. In order to work with such system, one need to be able to address individually each sites with a resolution under the standard PSF limit. We implemented a tunable sub-wavelength imaging system with a theoretical resolution of 30nm that we used to resolve the wave-packet of a cloud in a single lattice site. This scheme involves two superimposed optical lattices, one at 1064nm and one at 1529nm, whose interfringe can be tuned. We present hereafter the experimental setup in detail and show interesting results we obtained.