Upcoming seminars

Measurement disturbance tradeoffs in unsupervised quantum classification

Seminar date and time: 
2022-12-01 16:00
Author: 
Hector Spencer-Wood
Affiliation: 
University of Glasgow

We consider measurement disturbance tradeoffs in quantum machine learning protocols which seek to learn about quantum data. We study the simplest example of a binary classification task in the unsupervised regime. Primarily, we investigate how a classification of two qubits, that can each be in one of two unknown states, affects our ability to perform a subsequent classification on three qubits when a third is added. Surprisingly, we find a range of strategies in which a nontrivial first classification does not affect the success rate of the second classification.

Towards p-adic quantum bits via representations of the p-adic group of rotations SO(3)ₚ

Seminar date and time: 
2022-11-24 16:00
Author: 
Ilaria Svampa
Affiliation: 
GIQ and University of Camerino

We develop the p-adic quantum mechanics introduced by Volovich, where physics takes place in three-dimensional p-adic space rather than Euclidean space.
We study the p-adic rotation group SO(3)ₚ, and we outline a program to classify its continuous complex unitary projective representations.
These can be interpreted as a theory of p-adic angular momentum, where the p-adic qubit arises from those two-dimensional irreducible representations.

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Toy holography in dual-unitary circuits

Seminar date and time: 
2022-11-07 15:00
Author: 
Dr. Lluis Masanes
Affiliation: 
University College London

Dual unitaries are four-legged tensors which satisfy the unitarity condition across the time as well as the space direction. These have attracted a lot of attention in the last three years. One reason being that they allow for the construction of many-body models which display quantum chaos and are analytically tractable. In this talk will present a family of dual-unitary circuits in 1+1 dimensions which constitute discrete analogs of conformal field theories. In other words, these are quantum cellular automata which are scale and Lorentz invariant.

Quantum Chaos = Volume-Law Spatiotemporal Entanglement?

Seminar date and time: 
2022-11-03 16:00
Author: 
Neil Dowling
Affiliation: 
Monash University

Chaotic systems are highly sensitive to small perturbation, be they biological, chemical, classical, ecological, political, or quantum. Taking this as the underlying principle, we construct an operational notion for quantum chaos. Namely, we demand that the whole future state of a large system is highly sensitive to past operations on a small subpart of that system. This immediately leads to a direct link between quantum chaos and volumetric spatiotemporal entanglement.

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Entanglement catalysis for quantum states and noisy channels

Seminar date and time: 
2022-10-27 11:00
Author: 
Alexander Streltsov
Affiliation: 
University of Warsaw

Many applications of the emerging quantum technologies, such as quantum teleportation and quantum key distribution, require singlets, maximally entangled states of two quantum bits. It is thus of utmost importance to develop optimal procedures for establishing singlets between remote parties. As has been shown very recently, singlets can be obtained from other quantum states by using a quantum catalyst, an entangled quantum system which is not changed in the procedure. We put this idea further, investigating properties of entanglement catalysis and its role for quantum communication.

Location: 
GIQ seminar room
Contact: 
Andreas Winter

Landauer's principle with finite resources

Seminar date and time: 
2022-10-18 15:00
Author: 
Martí Perarnau-Llobet
Affiliation: 
University of Geneva

Landauer's principle states that a minimum amount of dissipation is required to erase one bit of information. Reaching this bound in practice requires infinite resources (either infinite time or infinite energy), a fact that is intimately connected to the second and third laws of thermodynamics. In the presence of finite resources, it becomes a challenging problem to identify optimal erasure processes that minimize the generation of dissipation. In this talk, I will present progress in this question based on a geometric approach to finite-time thermodynamics [1].

Location: 
GIQ seminar room

Abstracting a quantum computing stack: processes and challenges

Seminar date and time: 
2022-10-10 15:00
Author: 
Krishna Kumar Sabapathy
Affiliation: 
Independent researcher

In this talk I will provide a high level overview of the various modules that go into the design of a fault-tolerant quantum computer. I will use photonic quantum computers as a working example. Processes include state preparation, choice of computing model, quantum error correction, to list a few. I will also highlight some of the pressing open problems and challenges that lie ahead even from a theoretical point of view. Building low-error logical qubits in a scalable (modular) way remains the single core challenge impeding the deployment of usable quantum computing.

Location: 
GiQ seminar room.

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