Seminar: Bathen & Vines

It is a pleasure to invite you all to a MatMod / QHub / REGAL seminar by Marianne Bathen and Lasse Vines from the Department of Physics at the University of Oslo.

Quantum Technology (QT) studies at UiO
and teaching QT to 2nd year bachelor students

Abstract: In 2024, the University of Oslo started a new study direction within the Physics & Astronomy BSc programme on Quantum Technology (QT). The study direction aims at giving a broad overview of the topic, ranging from fundamental quantum physics and the quantum mechanics needed to utilize QT within the different applications, via physical realizations to quantum computing and quantum information science. The programme should prepare the students for various master programmes within QT, both at UiO and elsewhere.

The first QT related course in the study direction is found in the third semester, and titled “Fys1400 Introduction to quantum technology”. The course is given before the regular quantum physics course, and aims at giving a broad overview of the topic before the student dive into the various aspects of quantum physics and QT.

In this talk we will give a brief overview of the ongoing changes in the educational programmes at the Department of Physics at UiO, and give a brief overview and thoughts on teaching the introductory course in QT.

Time and Location

Wednesday March 26th, 14:00 – 15:00
Ellen Gleditschs hus (P35), room PS439

Seminar: Kristian Wold

It is a pleasure to invite you all to a MatMod / QHub / REGAL seminar by PhD candidate Kristian Wold from OsloMet – Oslo Metropolitan University.

Experimental Dissipative Quantum Chaos

Abstract: Classically chaotic systems are those where trajectories diverge exponentially as initial conditions are varied. However, it is not obvious how this can emerge from the more fundamental quantum mechanics, a linear theory. To see the connection, new mathematical tools for “Quantum Chaos” was developed, among them Random Matrix Theory (RMT) for studying quantum systems at the spectral level. Since its birth, RMT has been used to characterize signatures of chaos for closed quantum systems, both for theoretical models and physically realized experiments, showing good correspondence. 

More recently, RMT is being expanded to also treat dissipative quantum systems, inventing tools for detecting chaotic and integrable (non-chaotic) signatures for quantum systems influenced by noise from an environment. However, experimental insights have lagged behind. We substantiate the field of Experimental Dissipative Quantum Chaos by utilizing noisy intermediate-scale quantum (NISQ) computers as a tunable testbed for detecting dissipative quantum chaos. To do this, we have invented a gradient-based quantum tomography protocol, letting us model NISQ circuits as quantum channels from measurement data.

We find that parameterized quantum circuits produce spectra whose support closely follow that of the Diluted Unitary model, a two-parameter stochastic model. Further, we device a type of circuit that lets us engineer artificial noise predicted by RMT to exhibit integrability. We find that we have sufficient experimental fidelity and sensitivity to detect said integrability when implemented on hardware, showing that it is a suitable testbed for similar investigations. Lastly, we find that, when you run the circuit for sufficient depth, there is a transition between integrability and chaos, showing that the intrinsic noise of the hardware has a chaotic nature.

Time and Location

Wednesday March 12th, 13:00 – 14:00
Ellen Gleditschs hus (P35), room PS439

Seminar: Fabian Faulstich

It is a pleasure to invite you all to a lecture by Assistant Professor Fabian Faulstich from the Rensselaer Polytechnic Institute (RPI) in New York. The lecture will be given as a part of the Workshop on Quantum Theory: Foundations and Extensions of Density-Functional Theory held the same week.

A practical guide to quantum linear algebra

Abstract: We provide an introductory and practical guide to quantum phase estimation algorithms. We begin with a concise overview of the principles of qubits, focusing on state visualization, measurement intricacies, and their relationship to the classical eigenvalue problem. We introduce the Hadamard test and quantum phase estimation (QPE) as methods for eigenvalue approximation. For both algorithms, we detail their mathematical foundations, implementation steps, and error analyses, demonstrating how precision improves with increased measurements or ancilla qubits. Example simulations are performed using hardware emulators and the IBM Eagle One quantum machine, comparing the two approaches. Finally, we highlight the practical significance of QPE by applying it to the Transverse Field Ising Model, illustrating its utility in quantum physical systems.

The IBM Quantum System One at Rensselaer Polytechnic Institute, unveiled on April 5, 2024. Credit: IBM

About

Fabian has a background in mathematics, physics, and theoretical chemistry with a focus on problems arising from quantum many-body physics. In 2020, he earned his PhD in Applied Mathematics and Theoretical Chemistry from the University of Oslo. Currently, he servers as an Assistant Professor of Mathematics at RPI, where he also holds the Eliza Ricketts Foundation Career Development Chair.

His research focuses on advancing knowledge and methods for quantum many-body problems. His research involves the development, implementation, and mathematical analysis of cutting-edge numerical methods on classical as well as quantum machines.

Time and location

Wednesday December 4th, 11:00 – 12:00
Ellen Gleditschs hus (P35), auditorium PI646

On behalf of the organisers,
Vebjørn H. Bakkestuen
vebjorn.bakkestuen@oslomet.no

Seminar: Eva Lindroth and the Nobel prize

It is a pleasure to invite you all a seminar with prof. Eva Lindroth from Stockholm University.

Her background is with atomic, molecular and optical physics. Her contributions to the field is diverse and impressive. She is also a member of the Royal Swedish Academy of Sciences, Vice Chair for the class of Physics.

In this seminar she will tell us about the Nobel prize – naturally with emphasis on the physics prize. We will hear about how the laureates are elected. And she will tell us about particularly famous laureates such as Curie, Einstein and Meitner. Meitner is, perhaps, the most grave omission ever made when it comes to the physics prize.

Much of Eva’s research is very closely related to this year’s and last year’s Nobel prizes, the latter being awarded within the field of attosecond physics with her fellow Swede Anne L’Houllier as one of the recipients. This year’s prize is, of course, particularly interesting to our colleges at the AI group – highlighting the close connection between physics and AI.

Time: Wednesday 30th from 12.00

Place: PS439 in P35 (We will try to find a larger room if need be)

On behalf of the MatMod group and the Quantum Hub,

Sølve

Seminar: Frederik vom Ende

We invite all colleagues interested in open quantum systems and quantum information to the upcoming seminar by Frederik vom Ende from Freie Universität Berlin (please see the title and abstract below). The seminar will take place next Thursday, October 10th, at 13:00 in P35-PS439. Lunch will be provided on-site.

Quantum-Dynamical Semigroups and the Church of the Larger Hilbert Space

The idea underlying open systems theory is to describe the evolution of non-isolated systems—at least approximately—via a differential equation ρ'(t)=Lρ(t) with L of a special form, called Lindblad- or GKSL-form. This is, however, not the only way to tackle this problem; another successful approach is to consider the system coupled to its environment, and then extract the system’s dynamics by tracing out the environment from the combined unitary evolution. While the physics literature features well-known approximations which guarantee when these two descriptions are compatible, in this talk we will investigate under what conditions they can match precisely: Our main result is that GKSL-dynamics can be written exactly as the reduced evolution of system plus some environment if and only if the environment is infinite-dimensional with an overall unbounded Hamiltonian. In doing so we obtain a second-order Taylor-approximation for bounded system-environment Hamiltonians, with some familiar coefficients.

Seminar: Yves Rezus

It is a true pleasure to invite you to a seminar with our guest researchers Yves Rezus. Yves is spending this academic year on sabbatical and has chosen to come to us!

Do come and listen!

Abstract:

Encounters with single-quantum emitters

Yves Rezus

Amsterdam University of Applied Sciences (AUAS)

Single-quantum emitters are the smallest possible light sources. They consist of trapped atoms, molecules or engineered nanostructures, which emit one photon at a time. Research in single-quantum emitters has taken an enormous surge in the past few decades, leading to applications ranging from biological imaging to quantum computing.

In this talk I will give an experimental perspective on single-quantum emitters, focusing on what it takes to observe them in the laboratory and to exploit their properties in real-world applications. Along the way we will see what single-quantum emitters can teach us about fundamental quantum mechanics.

QBism as introduced by Anders Kvellestad

This Friday, 28th of June, we have the pleasure of hosting Anders Kvellestad, from the University of Oslo, who gave us an introduction to QBism!

That is a relatively new interpretation of quantum mechanics that emphasizes the role of the observer in defining quantum states. QBism, or Quantum Bayesianism, interprets quantum probabilities as personal beliefs about the outcomes of measurements, rather than objective properties of physical systems.

His lecture was thought-provoking and sparked a lively discussion with numerous questions from the audience (see photo). We are looking forward to his second seminar after the summer break, where he will delve deeper into the intricacies of QBism.

Cool workshop

From 9th to 12th of June, we had the pleasure of hosting a little workshop on atoms and lasers – and a couple of other things too. This was put together in connection with a visit from our esteemed colleges from Warsaw University, prof. Katarzyna Krajewska (picture), prof. Jerzy Kaminski (prince George amongst friends) and their team.

They all delivered very interesting presentations – as did Thomas Bondo Pedersen and his students from the Hylleraas Centre, which is headed by Thomas, and Morten Førre and his students. Presentations holding the promise of significant and new scientific contributions in the near future – both when it comes to pair creation, strong field ionization beyond the dipole approximation and the ability to describe complex, unbound molecular systems dynamically.

As for our local “hubbers”, our own Bendik got to demonstrate several of his very nice research results, and Sergiy gave a nice introduction to the diverse activities in our hub. We were happy to see the Regal fraction of our Quantum Hub, headed by Andre, taking and active part – both presenting and participating.

For more details – and a cool gallery, please visit the workshop’s homepage.

We thank Maryam Kaviani for taking care of virtually all practicalities. And we do not thank our technical division for remaining silent about the overly cool temperature in our original venue.

Commuting in a noncommutative space

Bridging quantum theory and gravitation is a great and mind-thrilling challenge. Non-commutative geometry is considered to be a candidate for such a bridge. This mathematical concept integrates quantum principles like the non-commutativity of operators into the fabric of spacetime.

We gained insights into this fascinating topic last Friday, April 12, from a talk by our guest speaker, Anna Pachol, an associate professor at the University of South-Eastern Norway. Anna provided an introductory overview of the field, which holds the potential to uncover the Holy Grail: a theory of quantum gravitation.

Although Anna resides in Oslo, she commutes to Kongsberg where the USN campus is located. If spacetime does indeed prove to be non-commutative (pending experimental verification or refutation), the title of this post will make perfect sense.