is an annual 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) is also welcome.
Previous QPL events were held in Paris (2020 - online), 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).
March 12th, 2021
May 7th, 2021
May 28th, 2021
June 2nd, 2021
June 7th to 11th, 2021
Note that the paper submission and author notification deadlines are both one month later than initially advertised.
All deadline times are Anywhere on Earth (UTC-12).
REMARK: Due to the COVID-19 pandemic, the conference might be shifted to online-only closer to the date. We will keep you posted!
Please make this conference a welcoming space for everyone. We ask you to use your real name when logging into any of our systems. Our conference is dedicated to providing a harassment-free conference experience for everyone, regardless of gender, gender identity and expression, age, sexual orientation, disability, physical appearance, body size, race, ethnicity, religion (or lack thereof), or scientific opinion. We do not tolerate harassment of community members in any form.
All communication should be appropriate for a professional audience including people of many different backgrounds. Sexual language and imagery is not appropriate for any venue this conference will be held in, whether physical or virtual. If you are being harassed, notice that someone else is being harassed, or have any other concerns, please contact a member of conference staff immediately. If a participant engages in harassing behaviour, the conference organisers may take any action they deem appropriate, including warning the offender or expulsion from the conference.
The dedicated safety and inclusion team will oversee reports of Code of Conduct violation. The team can be contacted at email@example.com , and its members are:
Harassment may include but is not limited to:
5 day event, 5 invited talks, 40 contributed talks, 20 posters, 100 participants.
The industry session will consist of an evening event starting with a presentation session shared by selected companies. These presentations will be followed by an industry fair, hosted together with the poster session.
QPL 2021 will also feature a virtual component, following the success of QPL 2020. Virtual participation will be enabled, talks will be streamed, and a virtual platform for scientific discussions will be implemented.
The abstracts of the talks presented at QPL 2021 have been compiled into a single Book Of Abstracts (pdf).
Recorded talks are available at the QPL 2021 Gdańsk Youtube Channel.
Part II of the earlier talk
Genuinely quantum SudoQ and its cardinality
Quantum Bell Nonlocality is Entanglement
Roberto Dobal Baldijão
Quantum Darwinism and the spreading of classical information in non-classical theories
A Deductive Verification Framework for Circuit-building Quantum
Compositional Models of Meaning on a Quantum Computer
Carlo Maria Scandolo
Jordan products of quantum channels and their compatibility
Invited Talk: Quantum networks and composition self-test all entangled states
Marek Żukowski and John Selby
Welcome to QPL2021 Gdansk
Invited Tutorial: Natural Language Processing and Quantum Theory
Xiaoning Bian and Sarah Li
Generators and Relations for On(ℤ[1/2]) and Uₙ(ℤ[1/2, i])
Hierarchy of Theories with Indefinite Causal Structures: A Second Look at the Causaloid Framework
Entangleability of cones
Bennett and Stinespring, Together at Last
The Stabilizer Subtheory Has a Unique Noncontextual Model
F-flow: determinism in measurement-based quantum computation with qudits
Conditional distributions for quantum systems
Graphical Language with Delayed Trace: Picturing Quantum Computing with Finite Memory
Alastair Abbott & Victoria Wright
Characterising and bounding the set of quantum behaviours in contextuality scenarios/Bounding and simulating contextual correlations in quantum theory
John van de Wetering
Constructing quantum circuits with global gates
Mutually unbiased bases and symetric informationally complete measurements in Bell experiments
The interplay of entanglement and nonlocality demystified: developing a new branch of entanglement theory
Diagrammatic Differentiation for Quantum Machine Learning
On non-commuting qubits, with an application to the closed time-like curve problem.
Consequences of preserving reversibility in quantum superchannels
Thermodynamics of Minimal Coupling Quantum Heat Engines
Quantifying causal influences in the presence of a quantum common cause
Quantum Algorithms and Oracles with the Scalable ZX-calculus
Invited Talk: A no-go theorem on the nature of the gravitational field beyond quantum theory
Coherent control and distinguishability of quantum channels via PBS-diagrams
Semi-Device-Independent Certification of Causal Nonseparability with Trusted Quantum Intputs
Invited Tutorial: Descriptive complexity as a tool for quantum correlations
Invited Talk: Incompatibility in general probabilistic theories, generalized spectrahedra, and tensor norms
Measurement simulability: overview and applications
Frank Fu, Kohei Kishida and Peter Selinger
Linear Dependent Type Theory for Quantum Programming Languages
Poster session and industry showcase
Causality in Higher Order Physics
Composites and Categories of Euclidean Jordan Algebras with Superselection Sectors
Relating measurement patterns to circuits via Pauli flow and Pauli Dependency DAGs
Industry Showcase featuring CQC, Google, Topos Institute, & Unitary Fund
Marco Túlio Quintino
Success-or-draw: A strategy allowing repeat-until-success in quantum computation
Agreement between observers: a physical principle?
John van de Wetering
The ZH-calculus: completeness and extensions
Invited Talk: A second-quantised Shannon theory
A generalised probabilistic theory featuring post-quantum steering
Self-testing is a method for certifying the production of quantum states with making minimal assumptions about the devices. In recent years a plethora of quantum states have been shown to be amenable to self-testing, but the question of whether an arbitrary quantum state can be self-tested, and up to which transformations, is an open question. I will show a method for self-testing an arbitrary (pure) quantum state, up to local transformations and global complex conjugation. The method is compositional in nature, utilising simple quantum networks with EPR pairs distributed throughout. I will also indicate how the global complex conjugation symmetry can be removed if the sources of EPR pairs are assumed to be independent. This is from joint work with Ivan Šupić, Joe Bowles, Marc-Olivier Renou and Antonio Acín.
Incompatibility of quantum measurements is one of the fundamental non-classical features of quantum theory. As a crucial ingredient in many quantum information protocols, incompatibility has become an important resource for quantum information theory, similar to entanglement. It is therefore a natural question how much of this resource is available in a given situation, characterized by the dimension of the quantum system, number of measurements and their outcomes.
It is known that incompatibility is not restricted to quantum mechanics but is present in any non-classical theory, in the framework of general probabilistic theories (GPT). This broader setting allows us to study and characterize incompatibility of measurements from different perspectives and using different mathematical tools. In this talk, we first concentrate on two-outcome measurements (or effects) and characterize their incompatibility in terms of tensor norms on Banach spaces. For measurements with more outcomes this does not seem possible, so we use a characterization by a GPT generalization of free spectrahedra and their inclusion constants, and by extensibility and separability properties of certain positive maps. As an application we explore compatibility regions and degrees of several GPT's of interest, in particular, we find a tight lower bound on incompatibility of any number of qubit effects.
The talk is based on a joint work with Andreas Bluhm and Ion Nechita, arxiv:2011.06497.
Recently, table-top experiments involving massive quantum systems have been proposed to test the interface of quantum theory and gravity. In particular, the crucial point of the debate is whether it is possible to conclude anything on the quantum nature of the gravitational field, provided that two quantum systems become entangled due to solely the gravitational interaction. Typically, this question has been addressed by assuming an underlying physical theory to describe the gravitational interaction, but no systematic approach to characterise the set of possible gravitational theories which are compatible with the observation of entanglement has been proposed. Here, we introduce the framework of Generalised Probabilistic Theories (GPTs) to the study of the nature of the gravitational field. This framework has the advantage that it only relies on the set of operationally accessible states, transformations, and measurements, without presupposing an underlying theory. Hence, it provides a framework to systematically study all theories compatible with the detection of entanglement generated via the gravitational interaction between two non-classical systems. Assuming that such gravitationally mediated entanglement is observed we prove a no-go theorem stating that gravity cannot simultaneously satisfy the following conditions i) it is a theory with no faster-than-light signalling; ii) it mediates the gravitational interaction via a physical degree of freedom; iii) it is classical. We further show what the violation of each condition implies, and in particular, when iii) is violated, we provide examples of non-classical and non-quantum theories which are logically consistent with the other conditions.
Traditionally, quantum Shannon theory has focused on scenarios where the internal state of the information carriers is quantum, while their trajectory is classical. However, as illustrated by the iconic double slit experiment, quantum particles can also propagate in a quantum superposition along multiple trajectories. In this talk, I shall discuss the recent extension of quantum Shannon theory to a second level of quantisation, where both the information and its propagation in spacetime is treated quantum mechanically.
First, I shall discuss our theoretical framework for formalising these scenarios, showing that when a single particle propagates through a superposition of multiple paths, the joint action of the independent noisy processes on each path is uniquely determined by their individual action on the vacuum state [G Chiribella & HK, Proc R Soc A 475.2225, 2019]. Secondly, I shall show how the same formalism can be extended further to describe the transmission of a quantum particle at a superposition of alternative moments in time [HK, W Mao, G Chiribella, arXiv:2004.06090, 2020]. When successive uses of a transmission line are correlated, we find that contrary to classical intuition, these correlations can be probed by a single quantum particle propagating at a superposition of times, and exploited to carry a larger amount of information per channel use.
Finally, I shall show that the mathematical structures arising in the physical scenarios of the second-quantised Shannon theory cannot be adequately described within the standard framework of quantum circuits. Consequently, I shall provide a brief introduction to our extended framework of routed quantum circuits [A Vanrietvelde, HK, J Barrett, arXiv:2011.08120, 2020], the details of which are left for another talk.
In this tutorial I will review some tools from theoretical computer science and descriptive complexity and show how can they be used to provide new insights into quantum foundations. In particular, I will show how Kolmogorov complexity and algorithmic randomness can be used in the context of quantum non-locality to analyse syntactic properties of sequences of experiments and provide a different notion of non-locality , new loopholes , new insight into the nature of quantum correlations  and open the doors into new informational principles for correlations.
Natural language processing (NLP) is a field of artificial intelligence that looks at representing natural language in a way that computers can take in, process, and interpret. One branch of NLP has had astonishing success over the last decade or so by representing words as vectors in vector spaces. A natural question then arises: can the tools and techniques of quantum theory be usefully applied in the area of NLP? In this tutorial I will give an overview of the use of vector semantics in NLP and an outline of applications of quantum techniques within NLP. These will include a principled approach to word and phrase composition in NLP, use of quantum structures such as density matrices for text representation, and an overview of how to move towards implementing these techniques on quantum computers.
Prospective speakers are invited to submit one (or more) of the following:
Proceedings submissions consist of a 5-12 page extended abstract. Only proceedings-track submissions are eligible to be published in Electronic Proceedings in Theoretical Computer Science (EPTCS) after the conference.
Non-proceedings submissions consist of a 3 page extended abstract and a link to a separate published paper, pre-print, or an attached draft.
Poster submissions consist of a 1-3 page abstract and may contain a link to a separate published paper or pre-print. Submission of partial results of work in progress is encouraged.
Submissions should be prepared using LaTeX, and must be submitted in PDF format. Use of the EPTCS style is encouraged. Submission is done via EasyChair: https://www.easychair.org/conferences/?conf=qpl2021
The Conference proceedings will be published in Electronic Proceedings in Theoretical Computer Science (EPTCS) after the conference. Only "proceedings submissions" are eligible to be published in the proceedings.
The deadline was the end of March the 12th "Anywhere on Earth" (UTC -12), and has now passed.
The conference will feature five days of scheduled talks by invited and contributed speakers, a poster session, and an industry session. QPL 2021 will also feature a virtual component, following the success of QPL 2020. Virtual participation will be enabled, talks will be streamed, and a virtual platform for scientific discussions will be implemented. More details comming soon.
We are available via email: QPL2021@gmail.com
If you are interested in more details about the event, want to know more about the sponsorship opportunities, please download the QPL2021 PDF Brochure.