Periodic Reporting for period 2 - OrbiDynaMIQs (Two-orbital quantum many-body systems: from Kondo dynamics to mediated interactions)
Okres sprawozdawczy: 2022-11-01 do 2024-04-30
Understanding the behaviour of quantum systems comprising many particles with strong mutual interactions is one of the most formidable challenges in physics. In the last decades, novel quantum technologies have been developed to address this challenge using tailored artificial quantum systems that allow to experimentally probe a quantum mechanical problem rather than calculating its solution with classical hardware. More recently, technical advances are driving the field of quantum science with cold atoms in the direction of studying many-particle systems with single-atom control. Much effort has been directed towards the implementation of the fundamental building blocks of a quantum processor, i.e. quantum gates, and, what's more, the high-fidelity control and imaging of individual atoms has opened exciting possibilities for realizing 'programmable' many-body systems in so-called quantum simulators, connecting to open questions in quantum matter and materials science.
The OrbiDynaMIQs project seeks to conduct quantum simulation experiments with ultracold fermionic atoms confined in laser-created optical lattices, allowing us to explore some amongst the intriguing phenomena characteristic of two-orbital quantum many-particle systems. Atoms moving in an optical lattice while occupying different long-lived electronic states share some strong analogies with electrons in the crystal lattice of multi-orbital materials, involving electrons that occupy distinct orbitals within each atom. The interaction between different orbitals gives rise to rich and striking behaviors, influencing a material's properties and underlying our understanding of strongly correlated materials. For example, the Kondo effect is a fascinating phenomenon arising in condensed matter from the interaction between localized electronic spins and itinerant electrons. In the Kondo effect, the presence of a single immobile magnetic impurity can constrain the motion of many surrounding particles, leading to a surprising increase of the electrical resistance at low temperatures from the collective screening of the impurity spin.
In our project we are working towards an atomic implementation of the Kondo effect and the rich many-body physics triggered by the competition between spin screening and long-range interactions mediated by mobile fermionic particles. For this goal, we are constructing a high-repetition rate quantum simulation apparatus based on fermionic ytterbiums atoms, where we exploit the versatility of optical tweezer arrays to facilitate high-fidelity state preparation and control of ultracold atoms in optical lattices. This innovative simulator will be instrumental in exploring the spatial and dynamical features of synthetic two-orbital fermionic systems, which go beyond the much-explored single-band Hubbard or polaron models and could give an alternative window of observation into open questions in condensed matter physics.
The OrbiDynaMIQs project seeks to conduct quantum simulation experiments with ultracold fermionic atoms confined in laser-created optical lattices, allowing us to explore some amongst the intriguing phenomena characteristic of two-orbital quantum many-particle systems. Atoms moving in an optical lattice while occupying different long-lived electronic states share some strong analogies with electrons in the crystal lattice of multi-orbital materials, involving electrons that occupy distinct orbitals within each atom. The interaction between different orbitals gives rise to rich and striking behaviors, influencing a material's properties and underlying our understanding of strongly correlated materials. For example, the Kondo effect is a fascinating phenomenon arising in condensed matter from the interaction between localized electronic spins and itinerant electrons. In the Kondo effect, the presence of a single immobile magnetic impurity can constrain the motion of many surrounding particles, leading to a surprising increase of the electrical resistance at low temperatures from the collective screening of the impurity spin.
In our project we are working towards an atomic implementation of the Kondo effect and the rich many-body physics triggered by the competition between spin screening and long-range interactions mediated by mobile fermionic particles. For this goal, we are constructing a high-repetition rate quantum simulation apparatus based on fermionic ytterbiums atoms, where we exploit the versatility of optical tweezer arrays to facilitate high-fidelity state preparation and control of ultracold atoms in optical lattices. This innovative simulator will be instrumental in exploring the spatial and dynamical features of synthetic two-orbital fermionic systems, which go beyond the much-explored single-band Hubbard or polaron models and could give an alternative window of observation into open questions in condensed matter physics.
The construction of a new laboratory has been the main focus of the work performed during the project's first half. Entirely built from the ground up, the ArQuS (Artificial Quantum Systems) laboratory infrastructure is operational and is the first atomic physics laboratory in the Trieste research system. The project's team has successfully finished setting up the experimental hardware for the cooling and trapping of individual ytterbium atoms in optical tweezers. The steps required to realize defect-free atomic arrays of fermionic atoms and assemble them into mesoscopic systems are currently being undertaken, including e.g. the developments of stable and tunable optical lattices. In parallel, the team is working on the local control of the internal atomic states, a key ingredient to introduce controlled quantum impurities (i.e. a second orbital) into the system and study their dynamics.
By the end of the OrbiDynaMIQs project, the team working in the ArQuS laboratory will have significantly enriched the experimental toolbox of neutral atom-based quantum simulators and atomtronics. An innovative approach to the creation of quantum many-particle systems, based on the assembly of individually tweezer trapped and laser cooled atoms, will enable rapid cycling to pursue high-statistics measurements of interparticle correlations. Compared to the traditional loading of optical lattice after an evaporative cooling stage, tweezer-based lattice implantation benefits from higher preparation fidelity and much shorter laser-cooling time scales, resulting in an expected increase of the experimental repetition rate by around one order of magnitude. Since each experimental cycle ends with an image of the atomic sample, corresponding to a projective measurement of the system's wavefunction, higher repetition rates lead to an improved sampling of the many-particle wavefunction, and thus to a more complete knowledge of the quantum state. Furthermore, combining optical tweezer potentials and optical lattices enables local optical addressing in an extended atomic system with unprecedented spectroscopic precision, utilizing the ultra-narrow clock transition connecting the lowest-lying singlet and triplet states of the ytterbium atom. We anticipate that after the successful completion of the full experimental apparatus, novel entangling gates based on inter-orbital spin exchange and high-fidelity large-scale quantum simulations of two-orbital Hubbard and Kondo-like models will be accessible.