14th Trieste–Ljubljana-Zagreb meeting, April 14th 2025, Zagreb


Date
Apr 14, 2025
Event
14th Trieste–Ljubljana-Zagreb meeting
Location
Zagreb
Bijenička cesta 46, Zagreb, 10000

On Monday April 14th 2025, Zagreb will host the 14th Trieste–Ljubljana-Zagreb meeting. This is a regular event attended by researchers from SISSA and ICTP (Italy), FMF UL and JSI (Ljubljana), and Ruđer Boškovič Institute (IRB, Zagreb) for scientists active on quantum many-body physics. The meeting is organized by the QTeam of IRB, but hosted by the neighbouring Institute for Physics (IFS, Bijenička Cesta 46, 10000, Zagreb, Croatia).

Remark: On Tuesday April 15th 2025, on the occasion of the World of Italian Research, the Italian Embassy in Croatia, with the help of IRB’s QTeam, is organizing a symposium on Quantum Technologies, whose program can be downloaded here. Everyone is welcome to attend and participate!

Time
10:30-11:00 Welcoming coffee break
11:00-11:30 Mark Arildsen - SISSA - Symmetry-Resolved Entanglement Entropy in a Non-Abelian Quantum Hall State: Quantum Hall states serve as an excellent platform for exploration of symmetry-resolved entanglement in the (2+1)-dimensional setting. Following on prior investigation of Abelian quantum Hall states [Oblak, Regnault, Estienne, PRB 105, 115131], we now compute the full counting statistics and symmetry-resolved entanglement entropies of the non-Abelian, bosonic Moore-Read quantum Hall state, with the aid of numerical computations from exact matrix product states. We find a form of equipartition of entanglement, up to finite-size corrections. We are also able to perform detailed analysis of the finite-size splittings of the symmetry-resolved entanglement spectrum using conformal field theory, which enables a granular understanding of the role of the finite-size corrections in a range of entanglement measures for these states.
11:30-12:00 Kohei Ogane - JSI -Ergodicity breaking crossover in two dimensions driven by Rydberg blockade: Ergodicity breaking is a phenomenon that isolated quantum systems avoid thermalization and has been studied predominantly in one-dimensional systems under quenched disorder. Two-dimensional ergodicity breaking is much less studied in comparison with that of one dimension. The reason is that numerically simulation of two-dimensional many-body systems is more difficult due to lattice structure. Two-dimensional ergodicity breaking phase is expected to disappear in the thermodynamic limit based on the avalanche scenario. However, the fate of the ergodicity breaking phase in the thermodynamic limit is controversial due to lack of understanding of two-dimensional ergodicity breaking. Inspired by experiments in the Rydberg atoms, I numerically calculated XXZ spin model where spins locate randomly with being subject to the Rydberg blockade. Since the model has no lattice structure, it is possible to test the system size dependence of entanglement entropy and participation entropy by exact diagonalization. I found that the critical disorder strength drifts slowly and robustly with system size and specified the ergodicity breaking crossover in finite system sizes.
12:00-12:30 Hernan Xavier - ICTP - Chiral gravitons on the lattice: Chiral graviton modes are exotic excitations tied to the underlying quantum geometry of fractional quantum Hall states. But do these persist on lattice models where continuum translations is broken and decay channels arise? In this talk, I introduce a field-theoretic framework that captures chiral graviton physics within the bosonic Harper-Hofstadter model. Backed by strong numerical evidence, we fin that these modes remain robust even in the presence of lattice effects, being well captured by our lattice ansatz. I’ll also highlight how geometric quenches offer a practical route to probing chiral gravitons in near-term quantum simulators.
12:30-14:30 Lunch & Discussion
14:30-15:00 Gianpaolo Torre - IRB - Experimental preparation of W-States through topological physics: W-states are important quantum states possessing both bi-partite and multi-partite entanglement and are necessary for several relevant quantum algorithms. We propose a protocol to generate them with an arbitrary number of qubits on a Rydberg atoms platform, by exploiting the principles of {\it topological frustration}. We experimentally achieve fidelities close to 90% (for 11 qubits) and show a promising scaling using accurate numerical simulations, with high fidelities for tens of qubits. In this way, not only do we reach an unparalleled accuracy for the generation of these states compared to the existing approaches, but we also show once more how physics principles can overcome traditional barriers and be exploited toward quantum advantage.
15:00-15:30 Francesco Gentile - SISSA - Entanglement hamiltonian of two disjoint blocks in the harmonic chain: I will talk about the entanglement Hamiltonian of two disjoint blocks in the harmonic chain on the line and in its ground state. In the regime of large mass, the non vanishing terms are only the on-site and the nearest-neighbour ones. Analytic expressions are obtained for their profiles, which are written in terms of piecewise linear functions that can be discontinuous and display sharp transitions as the separation between the blocks changes. In the regime of vanishing mass, where the matrices characterising the entanglement Hamiltonian contain couplings at all distances, we explore the location of the subdominant terms and some combinations of matrix elements that are useful for the continuum limit, comparing the results with the corresponding ones for the free chiral current. The single-particle entanglement spectra of these entanglement Hamiltonians are also investigated.
15:30-16:00 Coffee break
16:00-16:30 Rustem Sharipov - FMF - Ergodic behaviors in reversible 3-state cellular automata: Classical cellular automata represent a class of explicit discrete spacetime lattice models in which complex large-scale phenomena emerge from simple deterministic rules. With the goal to uncover different physically distinct classes of ergodic behavior, we perform a systematic study of three-state cellular automata (with a stable ‘vacuum’ state and ‘particles’ with ± charges). The classification is aided by the automata’s different transformation properties under discrete symmetries: charge conjugation, spatial parity and time reversal. In particular, we propose a simple classification that distinguishes between types and levels of ergodic behavior in such system as quantified by the following observables: the mean return time, the number of conserved quantities, and the scaling of correlation functions. In each of the physically distinct classes, we present examples and discuss some of their phenomenology. This includes chaotic or ergodic dynamics, phase-space fragmentation, Ruelle-Pollicott resonances, existence of quasilocal charges, and anomalous transport with a variety of dynamical exponents.
16:30-17:00 Gianni Aupetit-Diallo - SISSA - Accuracy of time-dependent GGE under weak dissipation: Unitary integrable models typically relax to a stationary Generalized Gibbs Ensemble (GGE), but in experimental realizations dissipation often breaks integrability. In this work, we use the recently introduced time-dependent GGE (t-GGE) approach to describe the open dynamics of a gas of bosons subject to atom losses and gains. We employ tensor network methods to provide numerical evidence of the exactness of the t-GGE in the limit of adiabatic dissipation, and of its accuracy in the regime of weak but finite dissipation. That accuracy is tested for two-point functions via the rapidity distribution, and for more complicated correlations through a non-Gaussianity measure. We combine this description with Generalized Hydrodynamics and we show that it correctly captures transport at the Euler scale. Our results demonstrate that the t-GGE approach is robust in both homogeneous and inhomogeneous settings
17:00-18:30 Poster session
19:00-21:00 Dinner

Useful information

Parking

Meeting location

  • Institute of Physics (IFS)
    http://ifs.hr/
    The meeting will be at the main conference all on the first floor of the 3rd wing. A member of our team will be waiting outside the IFS entrance.

Other information

  • Coffee breaks will take place at the meeting room at IFS
  • The lunch will be served at IRB.

Local Organizers: Fabio Franchini, Salvatore Marco Giampaolo, Gianpaolo Torre

Gianpaolo Torre
Gianpaolo Torre
Postdoctoral researcher