Hi all,
Tomorrow Martin Sandfuchs will tell us about his project with Ramona, entitled ''Computing key rates for device-independent quantum key distribution''. See below for the abstract. The talk will take place at 2pm in HIT F31.1 or on Zoom: https://ethz.zoom.us/j/362994444.
Best,
Ladina
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Abstract:
Quantum key distribution (QKD) aims to exploit the properties of quantum mechanics to produce a shared secret key between two distant users that is uncorrelated with the information held by an adversary. Device-independent QKD (DIQKD) tries to provide even stronger security guarantees by removing assumptions about how the devices operate. Unfortunately physical implementations of DIQKD pose significant experimental challenges and as a reaction a lot of theoretical work has gone into inventing improved protocols that can increase the tolerance to noise. A recent numerical method, developed by Peter Brown et al., has allowed for improved key rates in the asymptotic limit. In this presentation we demonstrate how this technique can be extended to the more realistic regime of finitely many key rounds. To do so we lower-bound the smooth min-entropy using the entropy accumulation theorem. We then build on previous DIQKD security proofs to propose a modified protocol which improves the threshold efficiency when performing DIQKD with lossy qubits.
Hi all,
Tomorrow Xavier Coiteux-Roy of USI Lugano will tell us about
"Quantum-resistant cryptography for Bennett-Maxwell demons". See below for
the abstract. The meeting will take place in HIT F13 and on zoom at the
usual address https://ethz.zoom.us/j/362994444.
Best,
Joe
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Title: Quantum-resistant cryptography for Bennett-Maxwell demons
Abstract: I will present how the second law of thermodynamics allows in
principle to achieve information-theoretically secure cryptographic
primitives such as secret-key establishment and oblivious transfer. While
idealized, our proposed protocols explore the limits of logically and
thermodynamically reversible computation and act as a focal point to
contrast the properties of information in different physical theories.
Hi all,
Tomorrow we'll hear from Alexander Schmidhuber, who did a semester project
with Esteban on "A covariant extension of the Page-Wootters mechanism to
spacetime". See the abstract below.
We can try a hybrid meeting for those who are at ETH and interested; I've
booked F31.1. The speaker will join us by zoom, so don't feel compelled to
join in person. The zoom link is the usual one,
https://ethz.zoom.us/j/362994444.
Best,
Joe
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Abstract:
Every observation in physics is made with respect to a frame of reference.
In any concrete scenario, this reference frame is constituted by a physical
system and thus subject to quantum phenomena such as entanglement and
superposition. A relativistic description of the laws of physics hence
needs to take into account such quantum reference frames. In this thesis,
we investigate a mechanism for temporal quantum reference frames developed
by Page and Wootters, and discuss its limitations. We show that two
a-priori different approaches to overcoming Kuchar's criticisms, developed
by Giovannetti, Lloyd & Maccone and Höhn, Smith & Lock, are equivalent.
Building upon this result, we construct a covariant extension of the
Page-Wootters mechanism to spacetime and derive the corresponding quantum
reference frame transformations for states and operators.
Dear all,
We are happy to invite you to a discussion group on philosophy and
foundations of physics involving members of the Theoretical Cosmology
and Quantum Information Theory groups. The group is open to students,
PhDs, Postdocs and Professors alike. We include a description of the
group and further details below, in case you are interested in
participating.
The motivation for this discussion group stems from the fact that a lot
of great physics, such as general relativity and quantum mechanics, has
been influenced by philosophical ideas. In turn, new physical and
mathematical insights have also sparked philosophical discussions. The
two disciplines are tightly related to each other and in many cases
there is no clear division between them.
We believe that discussions on philosophy and foundations deepen our
understanding of physics and mathematics. In our view, engaging in such
discussions can also guide our own research, sharpen our critical
thinking, and complement our computational, analytical and communication
skills. This view is also supported by the history of science, as great
insights have come from questioning the status quo, identifying biases,
prejudices or implicit assumptions. Furthermore, in recent years, there
has been a lot of interest and progress towards connecting ideas from
quantum information theory and gravity, which suggests the importance of
inter-disciplinary exchanges in making advances towards solving some of
the larger open problems in physics.
The spirit of these discussions is to promote exchanges between our
research groups in a flexible and open-minded manner. To get started, we
have compiled a list of topics that are potentially of interest to both
groups. This list of topics, along with a list of current participants
and potential guest speakers can be found at the following link. Any of
the participants are welcome to vote on existing topics, suggest further
topics and guest speakers. If you are interested in joining the group,
please request editing access on the google spreadsheet below, and also
include your details in the list of members, so that we can add you to
the mailing list for the group.
Once you have access to edit the spread sheet, you can vote on each of
the suggested topics, by clicking on the second tab, titled "List of
subjects and questions" and adding 1 to the corresponding entry in the
"vote" column. Please feel free to also add your topic and speaker
suggestions to the spreadsheet.
https://docs.google.com/spreadsheets/d/1FQ8-kvlKdu3mnVDjAP3FejzlXlCTotj5wlG…
In order to pick a suitable time for our first meeting, we have created
a doodle poll which is linked below. If you are interested in joining
the group, please fill out the poll as well. The first meeting would be
a good chance for all of us to get to know each other and decide on the
format of future meetings. If you would be joining, it would be great if
you could prepare to say a few sentences about yourself and your
research interests. We will aim to have the meeting in hybrid mode, with
the option of participating either in person or online. Once we have
finalised a date and time, we will inform you about the venue (if your
email is on the spreadsheet).
https://doodle.com/poll/5vybdcgufugcsxp2?utm_source=poll&utm_medium=link
We wish you a good end of the week and look forward to meeting and
getting to know you,
Best regards,
Fabio D'Ambrosio
Vilasini Venkatesh
Hi all,
Renato will deliver tomorrow's group seminar, on the topic of issues
surrounding the superposition of spacetime (if I understood
correctly). We will try a hybrid in-person / zoom event, starting at
2pm in HIT J52 and on zoom https://ethz.zoom.us/j/362994444.
Best,
Joe
Hi all,
Apologies, I was remiss in not sending out an announcement yesterday.
This afternoon Christophe will tell us about "Quasiprobability
simulation for computing", a means to get away with fewer qubits in
quantum computations. Join us at 2pm on zoom:
https://ethz.zoom.us/j/362994444
Best,
Joe
Hi all,
We're back tomorrow from the winter hiatus. Victor will tell us about
his latest research. We'll start at 2pm on zoom:
https://ethz.zoom.us/j/362994444.
Best,
Joe