QUACC+ (2025)

This conference has been supported by the Polish National Agency for Academic Exchange under the Welcome to Poland NAWA.

Funded by the National Science Centre, Poland, within the QuantERA II Programme that has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No 101017733.

About the Conference

Quantum Certification Conference+ (QUACC+), to be held on May 12 – 14, 2025 at the Center for Theoretical Physics PAS, Warsaw (Poland), aims to attract researchers working on widely understood quantum certification, and to inspire vivid scientific discussions and foster new collaborations. During the conference, attendees will have an opportunity to contribute a short talk (20 + 5 min) or a poster as well as listen to the invited talks (40 + 5 min) from the most prominent researchers in the field.

QUACC+ is a part of the QuantERA project “Verification of Quantum Technologies, Applications and Systems” (veriqtas.cft.edu.pl), and so it is also an opportunity for meeting between the research groups forming VERIqTAS consortium.

The conference fee is 100€.

bank account number: PL65 1130 1017 0020 1465 1320 0009
Center for Theoretical Physics
official address: al. Lotników 32/46
postal code and city: 02-668 Warsaw
country: Poland
put your name and "QUACC2025 conference fee" in the title

Contact: quacc2025{at}cft.edu.pl

Warning!
We have confirmed email scams targeting participants of QUACC 2025. Please ignore emails from "ops@travellerpoint dot org", or any other travel agency. Do not reply to the emails and do not click any links included in these emails.

Key Dates

April 10, 2025: deadline for abstracts of talks and posters
April 18, 2025: notification about talks and posters acceptance
April 24, 2025: registration is closed
April 28, 2025: programme is announced
May 8, 2025: payment deadline
May 12 – 14, 2025: conference days

Organizing Committees

Local Organizers (CFT PAN)

Remigiusz Augusiak
Wojciech Bruzda
Arturo Konderak
Jarek Korbicz

Scientific Committee:

Antonio Acín (ICFO, Barcelona)
Remigiusz Augusiak (CFT PAN, Warszawa)
Wojciech Bruzda (CFT PAN, Warszawa)
Omar Fawzi (Inria, ENS Lyon)
Arturo Konderak (CFT PAN, Warszawa)
Jarek Korbicz (CFT PAN, Warszawa)
Stefano Pironio (Université Libre de Bruxelles)

Invited Speakers

Antonio Acín (ICFO, Barcelona)
Certified Many-Body Physics When studying many-body systems, two approaches have been considered so far: analytical derivations and variational methods. The first provide exact results, as they do not involve any approximations, but scale exponentially with the number of particles, while the second scale much better but only provide estimates with no theoretical guarantees.
Polynomial optimisation methods offer an alternative approach somehow combining the advantage of exact and variational methods: it provides rigorous results, now in the form of upper and lower bounds, in a scalable way. We illustrate this new approach in two paradigmatic many-body problems: the estimation of expectation values in ground states of Hamiltonian operators and in steady states of quantum open systems.
Álvaro M. Alhambra (Instituto de Física Teórica – CSIC, Madrid)
Modelling Quantum Thermalization with Quantum Computers In quantum computing and simulation, one of our main goals is to efficiently mimic natural physical phenomena in a controlled manner. The process of thermalization is one such crucial task, for which recently there has been relevant progress.
In this talk, we will showcase important parts of this progress by introducing a recent dissipative evolution that models thermalization in the many-body setting, and that is efficiently implementable in a quantum computer. We then prove the following facts about this dissipative evolution:
1. It faithfully reproduces the dissipation induced by weak coupling to a bath.
2. In the high temperature regime, it very quickly approaches equilibrium.
3. In the low temperature regime, it yields a computational model with the same power as arbitrary quantum computations (BQP-complete).
Taken together, our results show that a family of quasi-local dissipative evolutions has the potential to mirror the success of classical Monte Carlo methods. I will also outline the opportunities that this presents for learning and verification of quantum statistical mechanics.
Nicholas Chancellor (Newcastle University)
Understanding and Improving Quantum Annealing     This talk will cover a number of efforts which I am involved in to understand how quantum annealing works in the diabatic regime which is currently experimentally accessible, work on problem encoding in quantum annealing, and a brief discussion on work I have been involved in related to optical optimisation devices. On the topic of understanding the diabatic setting I will review past work, and particularly discuss the relationship between annealing and continuous-time quantum walks. This will focus on understanding beyond the adiabatic theorem based on the energetics of the problem.
    I will then discuss recent work on this topic, including understanding how truly continuous time dynamics differs from gate-model digitisation in terms of solving optimisation problems, and efforts to use auxilliary qubits as an effective artificial bath which can aid problems solving by removing energy.
    I will then discuss work on problem encoding. The theme here will be the idea of using "hardware aware" encoding methods, in other words, methods based on the knowledge that the problem will eventually be embedded on a device with limited connectivity and where the number of variables in the encoding should be minimised. This includes techniques such as domain-wall encoding (which I will review), but also other methods.
    I will present examples where for example converting a quadratic constraint to a linear approximation can greatly reduce connectivity and therefore embedded problem size. I will also discuss a number of other techniques. A major theme here is that many considerations which are not considered very important in traditional optimisation become important when a problem is mapped to an analog annealer.
Omar Fawzi (Inria, ENS Lyon)
Generalized Quantum Asymptotic Equipartition We establish a generalized quantum asymptotic equipartition property (AEP) beyond the i.i.d. framework where the random samples are drawn from two sets of quantum states. In particular, under suitable assumptions on the sets, we prove that all operationally relevant divergences converge to the quantum relative entropy between the sets. More specifically, both the smoothed min- and max-relative entropy approach the regularized relative entropy between the sets. Notably, the asymptotic limit has explicit convergence guarantees and can be efficiently estimated through convex optimization programs, despite the regularization, provided that the sets have efficient descriptions.
At a technical level, we establish new additivity and chain rule properties for the measured relative entropy which we expect will have more applications. Based on joint work with Kun Fang and Hamza Fawzi arXiv:2411.04035 and arXiv:2502.07745.
Edwin Lobo (Université libre de Bruxelles)
Partial Joint-Measurability, Routed Bell Tests, and Their Application to DIQKD     Losses and noise in the transmission channel, which increase with distance, pose a major obstacle to photonics demonstrations of quantum nonlocality and its applications to device-independent protocols such as device-independent quantum key distribution (DIQKD).
    Recently, Masini et al [Quantum 8, 1574 (2024)] introduced the notion of partial-joint-measurability to study the limitations that arise from losses and noise in the certification of realistic quantum devices. We generalize this notion slightly and develop simple attacks for DIQKD and randomness generation protocols that can be carried out by an adversary Eve. Our attacks contradict some of the results in literature and shows that post-selection can leak information to Eve, even when Eve is assumed to be memoryless and acting in an i.i.d fashion.
     We then apply the insights gained from studying partial-joint-measurability to the certification of quantum correlations in Routed Bell experiments. In these experiments, Bob can route his quantum particle along two possible paths and measure it at two distinct locations – one near and another far from the source. We show that routed Bell protocols extend the distance over which quantum correlations can be certified compared to standard Bell experiments. Notably, quantum correlations generated by performing measurements on a two-qubit state can be used to certify quantum devices at arbitrary distances in a routed Bell experiment, provided Bob performs enough number of measurements.
     We also study routed versions of simple DIQKD protocols and show that they are more robust to losses and noise than standard DIQKD protocols.
Miguel Navascués (IQOQI, Vienna)
Extrapolation of Quantum Time Series     We consider the problem of predicting future averages of a collection of quantum observables, given noisy averages at past times. The measured observables, the initial state of the physical system and even the nature of the latter are unknown. We nonetheless assume a promise on the energy distribution of the state.
     For different types of energy constraints, we show that the optimal extrapolation can be computed up to arbitrary precision through hierarchies of semidefinite programs. Investigating to what extent extrapolation is possible in this framework, we discover highly problematic datasets that allow full predictability at time τ, but only when past averages are known up to precision superexponential in τ. We also find families of self-testing datasets, which allow full predictability under reasonable noise levels and whose approximate realization singles out specific Hamiltonians, states and measurement operators.
     We identify "aha! datasets", which drastically increase the predictability of the future statistics of an unrelated measurement, as well as fairly simple datasets that exhibit complete unpredictability at some future time τ, but full predictability at a later time τ' > τ.
Joschka Roffe (University of Edinburgh)
Quantum Error Correction with Quantum Low-Density Parity-Check Codes     In this talk, I will discuss recent progress in the design of quantum low-density parity-check (QLDPC) codes as a promising alternative to the surface code for fault-tolerant quantum computation. While QLDPC codes typically demand greater qubit connectivity than the surface code, they offer the potential for significantly reduced qubit overhead.
     I will outline methods for constructing QLDPC codes suitable for near-term devices and review recent developments in efficient compilation techniques for fault-tolerant logic.
     Finally, I will address the engineering challenges involved in designing decoders for QLDPC codes.
Francesco Tacchino (IBM Research Zürich)
Digital Quantum Simulations in the Era of Quantum Utility     Over the last few decades, quantum information processing has emerged as a gateway towards new, powerful approaches to scientific computing. Quantum technologies are nowadays experiencing a rapid development and could lead to effective solutions in domains ranging from fundamental physics and chemistry to life sciences, optimisation, and artificial intelligence.
    In this talk, I will review the state-of-the-art and recent progress in the field, with a focus on the theory of universal quantum simulators, utility-scale quantum computation and quantum-centric supercomputing. I will highlight recent milestone experiments, offering an overview of the IBM Quantum technology and software stack.
    I will then present selected applications in the domain of condensed matter and high-energy physics.
Yuming Zhao (University of Copenhagen)
An Operator-Algebraic Formulation of Robust Self-Testing     In this talk, I will introduce an operator-algebraic formulation of self-testing in terms of states on C*-algebras. Many nonlocal games of interest, including XOR games and synchronous games, have a "nice" game algebra in the sense that optimal/perfect strategies correspond to tracial states on the game algebra.
     For these nonlocal games, I will show how self-testing is related to the uniqueness of tracial states on the game algebras. I will also discuss the stability of game algebras and the robustness of self-tests.
     Based on arXiv:2301.11291 (with Connor Paddock, William Slofstra, and Yangchen Zhou) and arXiv:2411.03259.

Programme

schedule

book of abstracts

Venue

Center for Theoretical Physics of the Polish Academy of Sciences (CFT PAN) is a scientific institute. It was established in 1980 and conducts research in the field of theoretical physics, astrophysics and cosmology.

The building of CFT PAN is located in Służewiec – the southern district of the city. The address is Warszawa, Al. Lotników 32/46. Instructions/maps how to get there:

from the Central Railway Station
from Okęcie Airport
from Modlin Airport
from Warsaw West Bus and Train Station
from the nearest Metro station
public transport ticket prices

The organizers do not provide any accommodation. Please, search for accommodation on your own. Organizers do not pass any personal data to third parties in order to inform about possible accommodation places. Please do not answer any unexpected e-mails with respect to the hotel booking and never reveal your credit card number through e-mail or phone contact. Please contact any of LOC members if you need help.