Preface

This volume contains the proceedings of the 16th International Conference on Quantum Physics and Logic (QPL 2019), June 10-14, 2019 at Chapman University, Orange, California and was attended by 77 registered participants.

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 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 five invited lectures:

• John Baez (UC Riverside): Structured Cospans
• Anna Pappa (University College London): Classical computing via quantum means
• Joel Wallman (University of Waterloo): Contextuality, Quantum Computation, and the Church of the Larger Hilbert Space

It also included 2 invited tutorials:

• Ana Belen Sainz (Perimeter Institute): Bell Nonlocality - Correlations from Principles
• Quanlong Wang (University of Oxford) and KangFeng Ng (Radboud University): Completeness of the ZX Calculus

The conference program also included 45 contributed talks and 14 posters chosen from 69 total submissions. They were selected by the program committee, which was chaired by Bob Coecke and Matthew Leifer. The other members of the program committee were Miriam Backens, Giulio Chiribella, Ross Duncan, Stefano Gogioso, John Harding, Chris Heunen, Matthew Hoban, Dominic Horsman, Kohei Kishida, Aleks Kissinger, Joachim Kock, Ravi Kunjwal, Martha Lewis, Shane Mansfield, Dan Marsden, David Moore, Michael Moortgat, Daniel Oi, Ognyan Oreshkov, Anna Pappa, Dusko Pavlovic, Simon Perdrix, Neil Ross, Mehrnoosh Sadrzadeh , Ana Belen Sainz, Peter Selinger, Sonja Smets, Pawel Sobocinski, Robert Spekkens, Isar Stubbe, Benoit Valiron, Jamie Vicary, Alexander Wilce, Mingsheng Ying, Margherita Zorzi, and Magdalena Zych.

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

There were two submission categories at QPL 2019: 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 Sivert Aasnaess of Oxford University for the paper Cohomology and the Algebraic Structure of Contextuality in Measurement Based Quantum Computation.

The local organizers were Matthew Leifer, Lorenzo Catani, Justin Dressel, and Drew Moshier. The steering committee for the QPL conference series consists of Bob Coecke, Prakash Panangaden, and Peter Selinger. The conference enjoyed financial support from: Chapman University Office of the Provost; Chapman University Institute for Quantum Studies; Northrop Grumman; University of Waterloo Institute for Quantum Computing; Xanadu.

The PC Chairs,
Bob Coecke (University of Oxford) and Matthew Leifer (Chapman University).