Relativistic Quantum Information Forum - Recent Posts

Questions from the conference Observers and Causality in Quantum Gravity - 2026

Fabio Costa — Sat, 25 Apr 2026 14:15:38 +0000

At the recent conference Observers and Causality in Quantum Gravity, In Bratislava, there have been several interesting discussions on notions such as events, observers, reference frame, causality, as understood in different fields and by different people. We invite everyone from the RQI community to contribute to and extend this discussion here on the Forum. You can start by filling this survey.

Past WG2 seminars (video recording + slides)

Albert Roura — Thu, 23 Apr 2026 10:19:54 +0000

This thread will collect detailed information about past seminars, including links to the video recording and the presentation slides when available.

Upcoming WG2 Online Seminars

navdeeparya — Thu, 23 Apr 2026 08:59:44 +0000

Updates about the upcoming online seminars of the Working Group 2.

RE: Upcoming WG1 online Seminars

Vilasini — Wed, 08 Apr 2026 10:08:44 +0000

Hello everyone,

Hope you are doing well! The details of the next WG1 seminar are given below, please note the speaker update since the previous announcement. Due to a scheduling conflict, Maria Papageorgiou's talk has been postponed to a later date, and we are pleased to welcome Lin-Qing Chen as tomorrow's speaker.

Date and time: Thursday, 9th April, 15:00 CEST

Speaker: Lin-Qing Chen (IQOQI Vienna)

Title: Quantum coordinate transformations via matter fields

Abstract: A central challenge in quantum gravity is to formulate a theory without presupposing a background spacetime. Such a description requires relational observables and a genuinely quantum generalisation of diffeomorphisms. Here we associate coordinate systems with sets of four dynamical scalar fields, whose stress-energy tensors contribute to the constraints of linearised quantum gravity. Such quantum coordinate fields (QCFs) extend the notion of quantum reference frames and enable a relational description of other physical systems. By generalising the perspective-neutral construction of quantum reference frames, we show that relational, gauge invariant observables admit a description in each QCF perspective, and derive consistent transformations between perspectives. The resulting unitary maps implement local quantum coordinate changes, yielding quantum linearized diffeomorphisms beyond superpositions of classical ones. We further discuss the operational aspects of relational observables, the conceptual distinction between QCFs and quantum reference frames, and identify the difference between QCFs transformations and the superposition of classical diffeomorphisms.

Zoom link: https://york-ac-uk.zoom.us/j/95152863408?pwd=oKL9LKGpsOpUm1Ofxsj93SJLrgtns4.1

Hope to see you there! As you may know, the seminars are recorded and available on the RQI COST YouTube channel: https://www.youtube.com/@RQICOST

On behalf of:
Kasia Rejzner (Professor of Mathematics, University of York, WG1 leader)
V. Vilasini (Research Faculty in Quantum Information Theory, Inria, Université Grenoble Alpes, WG1 co-leader)

Conceptual Foundations of QFT Workshop, Vienna, 1-3 June 2026

Maria Papageorgiou — Mon, 02 Feb 2026 13:17:26 +0000

Registration is now open until February 28

https://www.iqoqi-vienna.at/news-events/conceptual-foundations-of-qft

Multi-time quantum process tomography on a superconducting qubit

Christina_giarmatzi — Thu, 22 Jan 2026 00:25:26 +0000

Current quantum technologies are at the cusp of becoming useful, but still face formidable obstacles such as noise. Noise severely limits the ability to scale quantum devices to the point that they would offer an advantage over classical devices. To understand the sources of noise it is necessary to fully characterise the quantum processes occurring across many time steps; only this would reveal any time-correlated noise called non-Markovian. Previous efforts have attempted such a characterisation but obtained only a limited reconstruction of such multi-time processes. In this work, we fully characterise a multi-time quantum process on superconducting hardware using in-house and cloud-based quantum processors. We achieve this by employing sequential measure-and-prepare operations combined with post-processing. Employing a recently developed formalism for multi-time processes, we detect general multi-time correlated noise. We also detect quantum correlated noise which demonstrates that part of the noise originates from quantum sources, such as physically nearby qubits on the chip.

Multi-Time Quantum Process Tomography On A Superconducting Qubit, Christina Giarmatzi, Tyler Jones, Alexei Gilchrist, Prasanna Pakkiam, Arkady Fedorov, Fabio Costa, Quantum 9, 1952 (2025). https://quantum-journal.org/papers/q-2025-12-18-1952/

Conceptual Foundations of QFT Workshop, Vienna, 1-3 June 2026

Maria Papageorgiou — Mon, 19 Jan 2026 16:37:59 +0000

Interdisciplinary workshop on the foundations of QFT uniting philosophical, historical, and mathematical perspectives of relativistic quantum physics.

link: https://www.iqoqi-vienna.at/de/news-events/conceptual-foundations-of-qft

RE: Upcoming WG1 online Seminars

Vilasini — Tue, 06 Jan 2026 12:46:33 +0000

Hello everyone!

We hope this message finds you well and wish you all the best for the New Year 2026!

This is to announce the schedule for the upcoming WG1 online seminars. We will not have a seminar in January as our usual schedule of 2nd Thursday of the month coincides with the holiday/travel season for most potential speakers and participants. The schedule for the next seminars from February to April are as follows.
The titles, abstracts and zoom links will be shared closer to the dates.

1. 12th February 2026 at 15:00 CET by Robert Oeckl (National Autonomous University of Mexico)

2. 12th March 2026 at 10:00 CET by Jan Mandrysch (IQOQI Vienna)

3. 9th April 2026 at 15:00 CET by Maria Papageorgiou (IQOQI Vienna)

Wish you a great first month of the year and hope to see many of you at the upcoming online seminars!

On behalf of:
Kasia Rejzner (Professor of Mathematics, University of York, WG1 leader)
V. Vilasini (Research Faculty in Quantum Information Theory, Inria, Université Grenoble Alpes, WG1 co-leader)

RE: STSM

Maria_Jivulescu — Thu, 18 Dec 2025 11:16:59 +0000

Hi, everybody! There is an open call for STSM and ITC&YR Grants, with deadline 15 January.

RE: Operational Models of Temperature Superpositions

CarolynWood — Wed, 17 Dec 2025 01:27:53 +0000

Apologies, the link above is a bit hard to see, and I'm not sure how to edit my post. Here are the paper details with the link:

Carolyn E. Wood, Harshit Verma, Fabio Costa, and Magdalena Zych, "Operational models of temperature superpositions", Phys. Rev. Research 7, 043243