May 2019 - ITP-quantumseminare - lists.phys.ethz.ch

tomorrow's group meeting E41.1 @ 3:30 pm
by Joe Renes 27 May '19

27 May '19

Hi all, This week Alastair Abbott is visiting from Geneva. Tomorrow he'll tell us about "Quantum Circuits with Classical and Quantum Control of Causal Orders". See below for the abstract. Best, -joe Abstract: The standard approach to quantum information processing, including the quantum circuit framework, implicitly assumes that operations are applied in a well defined causal order. However, quantum mechanics allows the order in which operations are applied to itself be in a quantum superposition. This observation has led to the process matrix formalism describing quantum processes without any global causal order. I will review a simple such process, the "quantum switch", that enables several advantages in quantum information. In fact, the quantum switch and its generalisation are thus far the only known "causally indefinite" processes for which a physical implementation is known to be possible. With this motivation, I will present two generalisations of standard quantum circuits: quantum circuits with classical and quantum control of causal order. These can be nicely characterised and the latter provides a concrete way of pursuing new noncausal processes that are, by construction, physically implementable.

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Last Brassard talk: Friday, 24th of May, 10:45, HIT F32.
by Lidia del Rio 23 May '19

23 May '19

Dear all, The last talk on local realistic theories by Gilles & Paul will take place tomorrow, Friday, 24th of May, 10:45, HIT F32. Best, Lídia

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today's meeting E41.1 @ 4pm
by Joe Renes 21 May '19

21 May '19

Hi all, today we have two semester project talks, one by Emanuel Malvetti, who worked with Raban, and one by Ivan Sergeev, who worked with Henrik. If it's no great inconvenience, we'll start at 4pm; apologies for the late announcement. Best, -joe

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Lecture Wednesday 13:45: Gilles Brassard & Paul Ramond-Robichaud
by Lidia del Rio 20 May '19

20 May '19

Dear all, Gilles and his former student Paul will continue the series of lectures on local realistic and non-signalling theories already this Wednesday. At the end of the lecture, we will arrange the time for the final lecture of the series. Best wishes, Lídia ---- Gilles Brassard and Paul Raymond-Robichaud Wednesday, 13:45, HIT K52 Local realistic and non-signalling theories. Lecture 2: Mathematical details Based on https://arxiv.org/abs/1710.01380 This is the second of a series of lectures in which we shall demonstrate the equivalence between local realistic and reversible-dynamics non-signalling theories of physics (which includes unitary quantum theory), Bell’s theorem notwithstanding. In the first lecture, we saw that it is possible for a local-realistic fantasy world to violate Bell’s inequality even more so than quantum theory. This sufficed to prove that no experimental violations of Bell’s inequality can be considered as proof, or even evidence, that our world cannot be both local and realistic: loophole-free experiments cannot exist by definition since the more experiments agree with the predictions of quantum theory, the more they give evidence that our world can be local and realistic! In the subsequent lectures, we will start with an easy (yet more substantial than in the first lecture) introduction to what we mean by realistic, local, and non-signalling. Then, we shall delve in the technical definitions of those notions and in the mathematical proof of equivalence between them provided the non-signalling theory exhibits reversible dynamics.

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Fwd: Quantum Computing Meetup
by Joe Renes 14 May '19

14 May '19

Hi all, Here is the email regarding the workshop on the IBM quantum computer. Best, -joe Begin forwarded message: *From:* Titus Neupert <titus.neupert(a)uzh.ch> *Date:* 13 May 2019 at 16:34:21 CEST *To:* <renner(a)ethz.ch> *Subject:* *Fwd: Quantum Computing Meetup* Dear Renato Here is the info about our mini-workshop on the IBM quantum computer. Anyone can join, but for people that want to join for dinner I would need to know by Tuesday afternoon (also whether vegetarian/special restrictions). Thanks! Best, Titus Begin forwarded message: *From:* Kenny Choo <kenny.choo(a)uzh.ch> *Date:* 30 April 2019 at 11:51:04 CEST *To:* Adam Smith <adam.smith.home(a)ntlworld.com>, "Knolle, Johannes" < j.knolle(a)imperial.ac.uk>, Nicolas regnault <regnaultn(a)gmail.com>, valentin.leeb(a)gmx.de, German Sierra <german.sierra(a)uam.es>, Frank Pollmann < frank.pollmann(a)tum.de> *Cc:* Titus Neupert <titus.neupert(a)uzh.ch> *Subject:* *Quantum Computing Meetup* Dear Quantum Computerists We are looking forward to welcoming you at University of Zurich in two weeks for our IBM quantum computing workshop. We would like to give you some more info about how May 16/17 will look like. We would like to make this event a little like an “un-conference”, i.e., only give a rough structure and rely on your creative input to fill the time. Everything will take place on the Irchel Campus of the University of Zurich, we have booked the room *Y34 J-01* (i.e, in building Y34) from Thu 10am to Fri 5pm. The one fixed thing is a talk by Ivano Tavernelli from IBM Zürich, on Friday 10 am. Around that we propose the following program: *Thu, May 16* 10.30-11.00 coffee chat 11.00-12.30 1st joint discussion session 12.30-14.00 lunch 14.00-15.30 2nd joint discussion session 15.30-16.00 coffee break 16.00-18.00 individual discussion/meeting session 19.00 dinner for all at Restaurant “Haus zum Rüden”, center of Zurich (we go there by tram) https://goo.gl/maps/3FsWU6rGk1yeyb7QA https://haus-zum-rueden.ch/?lang=en *Fri, May 17* 9.30-10.00 coffee chat 10.00-11.30 talk by Ivano Tavernelli +related discussion 11.30-12.30 3rd joint discussion session 12.30-14.00 lunch 14.00 onwards individual discussion/meeting session of course, we are open and flexible to adjust this. To fill the discussion times, please *prepare*: - a short talk (15 mins) about things that you already did on the IBM quantum computers, probably best done with slides; it is encouraged to present intermediate and unpublished results, any material that can inspire discussions is welcome - an idea of a future project that you want to pursue and we can discuss how to implement it etc. There will be blackboards in the room. Let us know if you have any questions or ideas for the meeting. Best regards Kenny and Titus

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tomorrow's group meeting E41.1 @ 4pm
by Joe Renes 13 May '19

13 May '19

Hi all, tomorrow David will tell us about his latest paper "Bounds on Lyapunov Exponents", https://arxiv.org/abs/1905.03270. We'll start at 4pm in the usual room, E41.1 (Elisa and I will be at the "Unterrichtskommissionssitzungen" (one word) downtown and hope to be back by then.) Best, -joe

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Tomorrow's meeting HPV G4 15:30
by Lidia del Rio 06 May '19

06 May '19

Dear all, Tomorrow our group meeting yields to a special seminar by Gilles Brassard. Note the unusual room. Cheers, Lídia *Gilles Brassard, Local realistic and non-signalling theories: Introduction* Tuesday, 7th of May 2019, 15:30, HPV G4, ETH Hönggerberg This is the first of a series of lectures in which I shall demonstrate the equivalence between local realistic and reversible-dynamics non-signalling theories of physics (which includes unitary quantum theory), Bell’s theorem notwithstanding. This first lecture will be given mostly as a public lecture set on a philosophical level, with no need for mathematical sophistication nor prior knowledge of quantum theory. In particular, we shall see that it is possible for a local-realistic fantasy world to violate Bell’s inequality even more so than quantum theory. This suffices to prove that no experimental violations of Bell’s inequality can be considered as proof, or even evidence, that our world cannot be both local and realistic: loophole-free experiments cannot exist by definition since the more experiments agree with the predictions of quantum theory, the more they give evidence that our world can be local and realistic! The subsequent lectures will delve in the technical definitions of local realism and of non-signalling, and in the mathematical proof of equivalence between those two notions, provided the non-signalling theory exhibits reversible dynamics. Attending the first lecture is highly recommended to those who wish to continue, but the first lecture can be enjoyed on its own. The first lecture will be based on https://www.mdpi.com/1099-4300/21/1/87 . The following lectures will be based on https://arxiv.org/abs/1710.01380 . This is joint work with Paul Raymond-Robichaud.

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