We consider the dynamics of a measured SYK model. The latter can be viewed as a universal many-body Hamiltonian for mesoscopic sized quantum systems. Focusing on the observable of state purification, we analytically describe the limits of strong and weak measurement rate, where in the latter case monitoring up to time scales exponentially long in the numbers of particles is required. We complement the analysis of the limiting regimes with the construction of an effective replica theory providing information on the stability and the symmetries of the respective phases. The analytical results are tested by comparison to exact numerical simulations.

Symmetry-enforced nodal-line semimetals are immune to perturbations that preserve the underlying symmetries. This fundamental robustness enables  investigations of fundamental phenomena and applications utilizing diverse  materials-design techniques. The drawback of symmetry-enforced nodal-line  semimetals is that the crossings of energy bands are constrained to symmetry- invariant momenta in the Brillouin zone. On the other end lies accidental nodal-line semimetals whose band crossings, not being enforced by symmetry,  are easily destroyed by perturbations. Some accidental nodal-line semimetals have, however, the advantage that their band crossings can occur in generic  locations in the Brillouin zone, and thus can be repositioned to tailor material properties. We show that lattice engineering with periodic distributions of vacancies yields a hybrid type of nodal-line semimetals which possess symmetry-enforced nodal lines and accidental nodal lines, with the latter endowed with an enhanced robustness to perturbations. Both types of nodal lines are explained by a symmetry analysis of an effective model which captures the relevant characteristics of the proposed materials and are verified by first-principles calculations of vacancy-engineered borophene and graphene polymorphs. Our findings offer an alternative path to relying on complicated compounds to design robust nodal line semimetals; one can instead remove atoms from a common monoatomic material.

The interplay between electronic interactions and disorder poses one of the most difficult problems in condensed matter systems. One-dimensional systems provide one of the few cases where reliable descriptions can be obtained. This is possible by means of a powerful Renormalization Group method developed towards the end of the 20th century. In this talk, I hope to describe the central ideas behind this method and to show some recent results. I will highlight some generic properties that can hopefully be useful in higher dimensions.

In this talk I will present an approach to describe the thermodynamic properties of nonequilibrium quantum systems at the nanoscale. One of the main difficulties of this kind of study – both at the classical and at the quantum level – is that such systems do not have a large number of constituents and, therefore, do not  satisfy one of the fundamental premises of microscopic theories that describe thermodynamic relationships. Another central problem is associated with the difficulty of making a distinction between the “system”, the “bath” and its “interfaces” in very tiny objects. I will discuss how to deal with these problems using the Landauer-Büttiker approach for the calculation of the entropy production in electronic transport. The latter reproduces the results of standard thermoelectric theories as well as approaches based on information theory,  besides allowing to calculate entropy fluctuations and study the newly proposed thermodynamic uncertainty relations (TUR). If time allows, I will show how the formalism can be extended to time-dependent systems, an essential element for understanding quantum engines.

Liquids are often considered an aggressive medium for standard electronics due to strong polarization effects and electrolysis [1]. However, they can turn advantageous, for example, to operate thin-film transistors (TFT) in the so-called solution-gated architecture [1-4]. In such devices, a drop of water, saline solution, or ionic liquid replaces the dielectric layer of regular TFTs, and an immersed gate electrode controls the device channel via the electrostatic coupling between ions and the semiconductor charge carriers [1–4]. In this talk, we will present the basics of solution-gated transistors, viz. types of device architecture, how to fabricate and operate them. We will discuss how such device platform can be used to electrically characterize thin films made of molecular/organic semiconductors and 2D materials (viz. liquid-phase exfoliated MoS2).
Finally, we will show how such devices can be used as powerful electrical transducers to develop chemical sensors and biosensors.

[1] T. Cramer, et al., J. Mater. Chem. B. 1, p. 3728–3741 (2013).
[2] R.F. de Oliveira, et al., Org. Electron. 31, p. 217–226 (2016).
[3] R. F. de Oliveira, et al., Adv. Func. Mater. 29, 1905375 (2019).
[4] F. Torricelli, et al., Nat. Rev. Methods Primers 1, 66 (2021).    

In the seminar, I would like to discuss the use of III-V semiconductor membranes as buildingblocks in nanotechnology by reviewing the fundamentals like the fabrication and basicproperties of membrane-based rolled-up tubes as well as flat membranes. Highlighting a recentexample, the influence of strain to the optical properties of rolled-up heterostructures has been investigated combining x-ray diffraction with photoluminescence spectroscopy and theoreticalcalculations. In the work, we have shown that not only a detailed understanding of the strain isnecessary to predict optical properties, but also that rolled-up tubes can be used to engineerthese properties in an elegant way. Moving away from three-dimensional structures formed by the release and rearrangement ofIII-V semiconductor membranes, I will briefly discuss the formation and application oftwo-dimensional, released III-V semiconductor membranes. Here, I would like to emphasize theuse as compliant or virtual substrates. For III-V membranes, we have demonstrated how such amembrane substrate influences the epitaxy of heterostructures. Moreover, we have proven thatoptical active structures can be grown on membranes and the emission is tunable by themembrane used as a virtual substrate.

References:
[1] N. Rodrigues, Leonarde; Scolfaro, Diego; Da Conceição, Lucas; Malachias, Angelo; Couto, Odilon D. D.; Iikawa, Fernando; Deneke, Christoph. Rolled-up Quantum Wells Composed of Nanolayered InGaAs/GaAs Heterostructures as Optical Materials for Quantum Information  Technology. ACS Applied Nano Materials, v. 4, p. 3140-3147, 2021.

[2] Garcia Jr., Ailton; Rodrigues, Leonarde N.; Covre da Silva, Saimon Felipe; Morelhão,  Sergio L.;Couto Jr., Odilon D. D.; Iikawa, Fernando; Deneke, Christoph. In-place bonded semiconductormembranes as compliant substrates for III-V compound devices. 
Nanoscale, v. 11, p. 3748, 2019.   

The journey and the entanglements intend to address what once the physicist John Ziman warned us about: "SCIENTISTS know philosophy and sociology as fish know water. They understand instinctively how to live in it without being aware that they are doing so.  That is, until the fish bowl is stirred or (horror!) overturned. We seem to be living in just such a time. Science is being shaken up and forced to abandon many of its cherished customs. We need to think hard about what is happening and what we should do, not merely to survive but to serve and delight humanity".   

Manganese oxides are of great scientific and technological relevance due to their wide range applications in catalysis, battery materials candidates, electrochemical electrodes, among others. Their properties are related to MnOx compounds chemistry-phase relationship to contain labile lattice oxygen and a particular density of Mn cations in a given oxidation state. For this reason, the growth of manganese oxides thin films on well-defined metal substrates has been widely explored in the literature. For this end, in this talk, I will discuss our own experimental findings on MnOx thin film growth on an Au(111) and Cu(111) substrates over a wide range of preparation conditions and film thicknesses investigated mainly by scanning tunneling microscopy (STM), low-energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS). We will discuss the formation of MnO and Mn3O4 oxide phase and structure, and the possible consequences to its electronic properties depending on the film surface orientation and substrate.

In the age of international super-collaborations, like LIGO, ESO, and neutrino telescopes and detectors, the LHC (Large Hadron Collider) is the large and complex proton-beans-collider with the mission of facing the challenges posed by advancing matter structure comprehension at the femto- and atto-scale. Its third round, forecast to start in March 2022, will launch an eighth experiment, FASER, which will join the ongoing Collaborations ALICE, ATLAS, CMS, LHCb, LHCf, MoEDAL and TOTEM.
    In this seminar, we will present the general structure of the primordial Universe phase transitions, the general frame of the Standard-Model of Fundamental Interactions (SM), and its 23 limiting problems. Starting from there, we will discuss the search for the so-called “New Physics” and how the LHC has confirmed theoretical results of the SM, revealing new categories of hadrons (tetra- and pentaquarks) and suggesting the existence of new particles and complex structures – to be probed more deeply in Run-3 – that were formed in physical conditions close to those in the ages of the great phase transitions, which gave origin to the SM physics. 

I will discuss the non-equilibrium dynamics in interacting systems subjected to quantum quenches. In such a process, a system is prepared in the ground state of a given Hamiltonian, we then introduce a sudden change in the system and let it evolves in time according to a new Hamiltonian. In the talk, I will introduce this subject and then exemplify it with results obtained in my group. 

In a first case [1], we connect two spin-1/2 XXZ chains prepared in different phases, one in the ferromagnetic phase and the other in the critical (Luttinger) phase. We show that the on-site magnetization and bipartite entanglement entropy follow effective light cones after the quench, which are determined by different types of excitations depending on the system parameters.

In a second case [2], a magnetic impurity is suddenly coupled to interacting chains. We find that the local magnetization at the impurity site decays faster if we increase the electronic interaction in the chains, even though the spin velocity decreases. At intermediate timescales, we obtain insights into the time evolution of the Kondo screening cloud in interacting systems.

[1] A. L. de Paula et al., Physical Review B 95, 045125 (2017).
[2] Helena Bragança et al., Physical Review B 103, 125152 (2021).