Preface

This volume contains the proceedings of the 20th International Conference on Quantum Physics and Logic (QPL 2023). The conference was held from 17 to 21 July 2023 at Institut Henri Poincaré in Paris, France.

Quantum Physics and Logic is a conference series that brings together academic and industry researchers working on mathematical foundations of quantum computation, quantum physics, and related areas. The main focus is on the use of algebraic and categorical structures, formal languages, type systems, semantic methods, as well as other mathematical and computer scientific techniques applicable to the study of physical systems, physical processes, and their composition. Work applying quantum-inspired techniques and structures to other fields (such as linguistics, artificial intelligence, and causality) is also welcome.

The QPL 2023 conference solicited four different kinds of submissions: proceedings submissions, non-proceedings submissions, poster submissions, and programming tool submissions.

Proceedings submissions were papers that were required to provide sufficient evidence of results of genuine interest. Authors of accepted proceedings submissions were given the opportunity to present their work during a talk at the conference and these papers were included in the proceedings of QPL 2023. No other kinds of submissions were considered for inclusion in the proceedings. Non-proceedings submissions consisted of a three page summary, together with a (link to a) separate published paper or preprint. Authors of accepted non-proceeding submissions were allowed to present their work in the form of a talk during the conference. Poster submissions consisted of a three page abstract of (partial) results or work in progress and authors of accepted poster submissions were invited to present their work during one of the poster sessions of the conference. Programming tool submissions consisted of three page descriptions of programming tools or frameworks. Authors of accepted programming tool submissions were given an opportunity to present their software during a dedicated "Software Session".

These proceedings contain 14 contributed papers that were selected for publication by the Program Committee. Papers submitted to QPL undergo a review process that is managed by members of the PC. The vast majority of submissions received at least three reviews. The selection of accepted papers was done through the use of the EasyChair conference management system following consideration of the submitted reviews and following (where necessary) discussion among the PC. The review process was single-blind: the identity of the authors is revealed to the reviewers, but not vice-versa. PC members were allowed to invite external experts to serve as subreviewers and to participate in the discussion of submissions which they were invited to review.

A record 152 submissions (excluding withdrawals and retractions) were considered for review by the PC. QPL 2023 had 54 accepted submissions in the non-proceedings track and 14 accepted submissions in the proceedings track. Most of the talks were presented during parallel sessions, but a selection of talks were presented during plenary sessions in the mornings. The program also had several poster sessions and one session dedicated to showcasing accepted programming tool submissions. There was also an industry session where industrial sponsors of QPL 2023 were given an opportunity to present their companies. The industry session consisted of two talks -- one by Quandela (Diamond Sponsor) and one by Quantinuum (Gold Sponsor).

The QPL 2023 conference featured an award for Best Student Paper. Papers eligible for the award were those where all the authors are students at the time of submission. The PC decided to award the Best Student Paper award for QPL 2023 to Cole Comfort (Department of Computer Science, University of Oxford) for his paper "The Algebra for Stabilizer Codes".

The official website of the conference is https://qpl2023.github.io/ and it contains a lot of relevant information about QPL 2023.

The Program Committee consisted of 42 members who were: Pablo Arrighi, Miriam Backens, Jonathan Barrett, Alessandro Bisio, Titouan Carette, Ulysse Chabaud, Giulio Chiribella, Bob Coecke, Alejandro Díaz-Caro, Ross Duncan, Pierre-Emmanuel Emeriau, Yuan Feng, Stefano Gogioso, Amar Hadzihasanovic, Emmanuel Jeandel, Martti Karvonen, Kohei Kishida, Aleks Kissinger, Ravi Kunjwal, Shane Mansfield (co-chair), Simon Martiel, Konstantinos Meichanetzidis, Mio Murao, Ognyan Oreshkov, Prakash Panangaden, Simon Perdrix, Neil Ross, Ana Belén Sainz, Carlo Maria Scandolo, John Selby, Peter Selinger, Rui Soares Barbosa, Pawel Sobocinski, Isar Stubbe, Benoît Valiron (co-chair), Augustin Vanrietvelde, Renaud Vilmart, Quanlong Wang, John van de Wetering, Alexander Wilce, Mingsheng Ying, and Vladimir Zamdzhiev (co-chair).

The Organising Committee consisted of eight members who were: Ulysse Chabaud, Pierre-Emmanuel Emeriau, Shane Mansfield, Simon Perdrix, Benoît Valiron, Augustin Vanrietvelde, Renaud Vilmart, and Vladimir Zamdzhiev.

The QPL Steering Committee consisted of Bob Coecke, Prakash Panangaden, and Peter Selinger.

We wish to thank all the members of the PC for their work in selecting the program of QPL 2023. We also thank all external subreviewers for their help and also the authors for their submissions to QPL 2023. Thanks also go to Ulysse Chabaud for making a few decisions on papers for which the PC co-chairs were not available. We are grateful to the EPTCS team for their help in preparing the proceedings of the conference. We also thank the members of the Organising Committee for their help in setting up the conference. We also thank the student helpers who volunteered to assist us: Dogukan Bakircioglu, Marin Costes, Kinnari Dave, Nicolas Heurtel, Paraskevi Kasnetsi, Charlène Laffond, Julien Lamiroy, Louis Lemonnier, Tianyi Li, Quan Long, Fatima-Zahra Merimi, Octave Mestoudjian, Ramdane Mouloua, and Sunheang Ty. Thanks also go to the staff of Institut Henri Poincaré who helped us with the organisation of the conference. Finally, we thank the QPL steering committee for their support and we thank all people who have contributed to the success of QPL 2023.

QPL 2023 received (financial) support from Quandela (Diamond Sponsor), Quantinuum (Gold Sponsor), The University of Chicago (Silver Sponsor), and Inria (Organisational Support and Funding).

August 2023,
Shane Mansfield, Benoît Valiron, and Vladimir Zamdzhiev