1. Seminários da Óptica e Informação Quântica – Emma Pearce

    Infrared imaging and sensing with undetected photons: smaller, faster, brighter, longer

    Emma Pearce
    (Imperial College London)

    Imaging in the infrared is utilised across many scientific disciplines, from material analysis to diagnostic medicine. However, applications are often limited by inefficient, noisy detectors as well as expensive infrared sources. Infrared imaging with undetected photons allows us to harness the information in the infrared while using the superior detection technology available in the visible range.

    In this talk, I will cover the work undertaken at Imperial College London over the past two years to explore both fundamental and practical aspects of this technique. I will first present a compact, robust, and portable system developed to demonstrate imaging with undetected photons outside of a lab environment, including a real-time analysis interface. I will go on to discuss a scheme that can compensate for losses in the system and reduce the power reaching the sample while maintaining a detectable signal. Finally, I will present recent theoretical and experimental results on using a stimulated non-linear process to enhance image quality.

    Link Zoom: https://umassboston.zoom.us/j/97176584442

    Grupo de Óptica e Informação Quântica
    Instituto de Física UFRJ


  2. Seminários da Óptica e Informação Quântica – Vitalie Eremeev

    High-fidelity synchronization and transfer of quantum states in
    optomechanical hybrid systems
    Vitalie Eremeev

    (Facultad de Ingeniería y Ciencias, Universidad Diego Portales, Santiago, Chile)


    In a hybrid quantum system, consisting of a three-level atom, cavity and mechanical oscillator (see Fig. 1a), we study the effects of synchronization and transfer of nonclassical states between the mechanical oscillator and the cavity field. As results, we show that an initially thermalized mechanical oscillator when connected to a squeezed bath, it evolves to a squeezed state which in steady state is synchronized with the cavity mode (see Fig. 1b). On the other hand, if the mechanical oscillator is initially prepared in a nonclassical state, e.g. squeezed and Schroedinger’s cat states, while the cavity is in a thermal state, then a periodic transfer between the mechanical oscillator and cavity mode occurs for given interaction times. As qualitative results, we prove that the synchronization and transfer of the quantum states are feasible with high fidelity. These effects are realizable in the regime of weak optomechanical coupling; however the fidelity can be improved by enhancing the optomechanical and Jaynes-Cummings couplings and reducing the loss rates, which is technologically attainable nowadays. 
     Reference: H. Molinares, V. Eremeev, M. Orszag, Phys. Rev. A 105, 033708 (2022).








    Grupo de Óptica e Informação Quântica
    Instituto de Física UFRJ

  3. Seminários da Óptica e Informação Quântica – Marcio Taddei

    Efficiently measuring many-body quantum systems
    Marcio Taddei

    (ICFO – The Institute of Photonic Sciences, Barcelona)


    Reconstructing the full quantum state of a many-body system requires the estimation of a number of parameters that grows exponentially with system size. Nevertheless, there are situations in which one is only interested in a subset of these parameters and a full reconstruction is not needed. A paradigmatic scenario is that where one aims at determining all the reduced states up to a given size. This is achieved by overlapping tomography, which we review here; it makes strong use of parallelization to address this problem with a number of product measurements much smaller than what is obtained when performing independent tomography of each reduced state.
    There are however many relevant physical systems with a natural notion of locality where one is mostly interested in the reduced states of neighboring particles. We introduce local overlapping tomography, aimed at that case (arXiv:2112.03924). First of all, we show that, contrary to its full version, the number of product measurements needed for local overlapping tomography does not grow with system size. Then, we present strategies for qubit and fermionic systems based on graph-coloring results, and also examples in selected lattice geometries.
    Finally, we present perspectives for further work on the question of when overlapping tomography is (almost) sufficient for full state description.


    Meeting ID: 880 8053 2007
    Passcode: 392159

    A sala estará aberta a partir das 15H15.

    Grupo de Óptica e Informação Quântica
    Instituto de Física – UFRJ

  4. Seminários da Óptica e Informação Quântica – Abasalt Bahrami

    Hybird Atom-Ion Quantum Simulator 
    Abasalt Bahrami 

    (Johannes Gütenberg-Universität Mainz & PostDoc at UCLA)


    In order to study interactions of atomic ions with ultracold neutral atoms, it is important to have sub-µm control over positioning ion crystals. We introduced a microfabricated planar ion trap which can simultaneously trap single Yb+ ions and 87Rb atoms in mirror-magneto optical trap (mMOT). To assure stable positioning of ion crystals with respect to trapped neutral atoms, we integrated into the overall design a chip-based Ioffe-Pritchard trap potential formed by a Z-shaped wire and an external bias magnetic field. The potential applications of our system would be detecting the magnetic field gradient produced by the magnetic dipole moment of a few atoms by using ions in an entangled state. It also features close analogies to natural solid-state systems, as the atomic degrees of freedom couple to phonons of the ion lattice, thereby emulating a solid-state system.


    Meeting ID: 842 1315 7623

    Passcode: 150130

    A sala estará aberta a partir das 15H15.


    Grupo de Óptica e Informação Quântica
    Instituto de Física UFRJ