Published: 6th September 2021
DOI: 10.4204/EPTCS.340
ISSN: 2075-2180

EPTCS 340

Proceedings 17th International Conference on
Quantum Physics and Logic
Paris, France, June 2 - 6, 2020

Edited by: Benoît Valiron, Shane Mansfield, Pablo Arrighi and Prakash Panangaden

Preface
Pablo Arrighi, Shane Mansfield, Prakash Panangaden and Benoît Valiron
Equivalence of Grandfather and Information Antinomy Under Intervention
Ämin Baumeler and Eleftherios Tselentis
1
Well-tempered ZX and ZH Calculi
Niel de Beaudrap
13
Tensor Network Rewriting Strategies for Satisfiability and Counting
Niel de Beaudrap, Aleks Kissinger and Konstantinos Meichanetzidis
46
The ZX&-calculus: A complete graphical calculus for classical circuits using spiders
Cole Comfort
60
Dichotomy between Deterministic and Probabilistic Models in Countably Additive Effectus Theory
Kenta Cho, Bas Westerbaan and John van de Wetering
91
Putting a Spin on Language: A Quantum Interpretation of Unary Connectives for Linguistic Applications
Adriana D. Correia, Henk T. C. Stoof and Michael Moortgat
114
Hyper-decoherence in Density Hypercubes
James Hefford and Stefano Gogioso
141
Contextuality and Expressivity of Non-locality
Sacha Huriot-Tattegrain and Mehdi Mhalla
160
Quantum CPOs
Andre Kornell, Bert Lindenhovius and Michael Mislove
174
Hypergraph Simplification: Linking the Path-sum Approach to the ZH-calculus
Louis Lemonnier, John van de Wetering and Aleks Kissinger
188
Quantum Natural Language Processing on Near-Term Quantum Computers
Konstantinos Meichanetzidis, Stefano Gogioso, Giovanni de Felice, Nicolò Chiappori, Alexis Toumi and Bob Coecke
213
AND-gates in ZX-calculus: Spider Nest Identities and QBC-completeness
Anthony Munson, Bob Coecke and Quanlong Wang
230
Giving Operational Meaning to the Superposition of Causal Orders
Nicola Pinzani and Stefano Gogioso
256
Gottesman Types for Quantum Programs
Robert Rand, Aarthi Sundaram, Kartik Singhal and Brad Lackey
279
Quantum Hoare Type Theory: Extended Abstract
Kartik Singhal and John Reppy
291
An Algebraic Axiomatisation of ZX-calculus
Quanlong Wang
303
A Diagrammatic Approach to Information Transmission in Generalised Switches
Matt Wilson and Giulio Chiribella
333

Preface

This volume contains the proceedings of the 17th International Conference on Quantum Physics and Logic (QPL 2020), which was held online together with MFPS 2020 on June 2–5, 2020.

The conference took place on the communication platform Slack which allowed for text-based community interactions, and on Cisco-Webex/Zoom for the live talks, which were also broadcasted on YouTube. Over 400 people registered on Slack and more than 15k messages were exchanged during the week. On average, between 40 and 80 people attended the talks during the live broadcasts. The ability to watch video recordings at a later time also proved popular, and some of the videos had reached several hundred views by the end of the week.

QPL is a conference that brings together researchers working on mathematical foundations of quantum physics, quantum computing, and related areas, with a focus on structural perspectives and the use of logical tools, ordered algebraic and category-theoretic structures, formal languages, semantical methods, and other computer science techniques applied to the study of physical behaviour in general. Work that applies structures and methods inspired by quantum theory to other fields (including computer science) was also welcome.

Previous QPL events were held in Orange (2019), Halifax (2018), Nijmegen (2017), Glasgow (2016), Oxford (2015) Kyoto (2014), Barcelona (2013), Brussels (2012), Nijmegen (2011), Oxford (2010), Oxford (2009), Reykjavik (2008), Oxford (2006), Chicago (2005), Turku (2004), and Ottawa (2003).

The QPL conference program included 4 invited speakers:

QPL and MFPS also shared 4 invited speakers during a joint session:

The conference program included 42 contributed talks selected from a total of 58 submissions. They were selected by the program committee, which was chaired by Pablo Arrighi, Shane Mansfield, Prakash Panangaden and Benoît Valiron. The other members of the program committee were Miriam Backens, Jon Barrett, Dan Browne, Giulio Chiribella, Bob Coecke, Alejandro Diaz-Caro, Ross Duncan, Yuan Feng, Simon Gay, Stefano Gogioso, Chris Heunen, Matthew Hoban, Dominic Horsman, Aleks Kissinger, Joachim Kock, Martha Lewis, Dan Marsden, Simon Martiel, Michael Moortgat, Ognyan Oreshkov, Simon Perdrix, Paolo Perinotti, Neil Ross, Ana Belén Sainz, Mehrnoosh Sadrzadeh, Peter Selinger, Pawel Sobocinski, Isar Stubbe, Jamie Vicary, Alexander Wilce, Margherita Zorzi, Magdalena Anna Zych.

Each submission was thoroughly refereed by the program committee, and reviewers delivered detailed and insightful comments and suggestions. The program chairs thank all the program committee members and all of the additional reviewers for their excellent service.

There were two submission categories at QPL 2020: original contributions, consisting of a 5–12 page extended abstract, and extended abstracts of work published or submitted elsewhere. This volume contains papers corresponding to a selection of the original contributions.

At each QPL conference, an award for the best student paper is given at the discretion of the program committee. Papers eligible for the award are those where all the authors are students at the time of submission. This year's best student paper award went to Cole Comfort of Oxford University for the paper “The ZX& calculus: A complete graphical calculus for classical circuits using spiders”.

The (non-)local organizers were Pablo Arrighi, Aleks Kissinger, Shane Mansfield, Benoît Valiron, John van de Wetering, Matthew Wilson, and Vladimir Zamdzhiev.

The steering committee for the QPL conference series consists of Bob Coecke, Prakash Panangaden, and Peter Selinger. The conference enjoyed financial support from:

To conclude, the chairs would like to deeply thank John van de Wetering and Matthew Wilson for their dedication in designing a simple, yet resilient protocol for broadcasting both live and pre-recorded talks online. They spent a week, full-time, testing out various combinations of tools to put everything in place. Together with our awesome team of Ph.D students, Agustin Borgna, Dongho Lee and Kostia Chardonnet, they strived to make QPL 2020 the success that it was.

The PC Chairs,
Pablo Arrighi (Université Paris-Saclay), Shane Mansfield (Quandela), Prakash Panangaden (McGill University) and Benoît Valiron (Université Paris-Saclay).