DQMP Forum - Greta Segantini - Carlos Bolech Gret

13.05.2025 13:00 – 14:00

Study of Ferroelectric and Mechanical Properties of Oxide Membranes
Greta Segantini(group of prof. Triscone and prof. Caviglia)

Transition metal oxides display a wide range of functionalities, including ferroelectricity,ferromagnetism, and hightemperature superconductivity. Epitaxial growth enables the synthesis of highquality films, yet it confines the choice of growth substrates to those meeting symmetry and lattice parameter constraints, thereby limiting technological applications of epitaxial oxides. To overcome these constraints, oxide layers can be released from their growth substrates using sacrificial layers, resulting in freestanding membranes.
This approach enables non-epitaxial stacking and the fabrication of novel synthetic heterostructures. In ferroelectric perovskites, membrane release alters electrostatic and mechanical boundary conditions, allowing domain configurations and mechanical deformations that are unattainable in conventional epitaxial films. Ferroelectric oxide membranes exhibit unique states that could unlock novel mechanical properties, which hold great potential for next generation electronic devices.


Data Compression and Cold-atom Condensates
Carlos Bolech Gret (visitor of prof. Giamarchi)

We shall begin with a general discussion of data compression strategies and tradeoffs. Which will allow us to put into perspective the needs that one faces in the context of the quantum many-body problem.
We will argue that, for a large class of one-dimensional lattice problems, those needs are optimally met using the so-called Matrix Product States (MPS) ansatz. Starting from there and based on a formulation of MPS in the continuum (cMPS), we have proposed a matrix ansatz that approximates well the ground states of quantum degenerate gases of interacting bosons, spin-1/2 fermions, or their mixtures. We can deal with arbitrary combinations of masses and interactions (but always in one spatial dimension). In the special cases of integrable systems, we showed that a cMPS ansatz not only recovers most aspects of the exact solutions but can also access quantities beyond those readily available from Quantum Inverse Scattering (Bethe Ansatz).

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückelberg

entrée libre