About me

I am currently (since March 2017) a Senior Postdoc at the Institute for Quantum Optics and Quantum Information (IQOQI) in Vienna in the group of Marcus Huber.

My research interests lie in the overlap of quantum information & computation with  quantum optics and quantum thermodynamics. Recently, I have been interested in investigating the connections between resources for quantum computation and quantum metrology. See the Research Section of my homepage for more details.

Previously, I have worked as a Postdoc (Universitätsassistent) at the Institute for Theoretical Physics of the University of Innsbruck, working in the Quantum Information & Computation group with Prof. Hans J. Briegel, where I have also been teaching courses in theoretical physics. I obtained my PhD (2010-2013) under the supervision of Ivette Fuentes at the University of Nottingham. Before that, I worked in the particle physics group at the Faculty of Physics at the University of Vienna, where I studied for my diploma, supervised by Reinhold A. Bertlmann.
Contact
Nicolai Friis
Senior Postdoc
Institute for Quantum Optics and Quantum Information
Austrian Academy of Sciences
Boltzmanngasse 3
1090 Vienna, Austria
e-mail: nicolai.friis@univie.ac.at

News

The second installment of our investigation of the usefulness and limitations of Gaussian operations in quantum thermodynamics is now available on the arXiv: Precision and Work Fluctuations in Gaussian Battery Charging, has now been published in Quantum 2, 61 (2018).
In a recent collaboration with Innsbruck and Ulm, we have been able track the dynamics of the development of genuine multipartite entanglement in groups of up to 5 neighbours in a chain of 20 fully controlled trapped-ion qubits. The paper hast just been published in Physical Review X [Friis, Marty et al., Phys. Rev. X 8, 021012 (2018)]. (Image credit: IQOQI Innsbruck/Harald Ritsch)

Press release from IQOQI Innsbruck (English),
Phys.org (English), IEEE Spectrum (English)
Austrian news (in German): ORF & der Standard
Our paper on "Flexible resources for quantum metrology", New J. Phys. 19, 063044 (2017) [arXiv:1610.09999], discussing how 2D cluster states can be used as resources for parameter estimation, has been selected by the editors of New Journal of Physics for inclusion in the 'Highlights of 2017' collection.
I feel very honored and happy to have been selected as the recipient of the Entropy 2018 Young Investigator Award. On this occasion I will give a talk at the conference “Entropy 2018: From Physics to Information Sciences and Geometry”.
A preprint of our review "Trade-Off Between Work and Correlations in Quantum Thermodynamics" has just appeared online [Vitagliano, Klöckl, Huber, Friis, arXiv:1803:06884]. It will features as a chapter in the upcoming book "Thermodynamics in the Quantum Regime - Recent Progress and Outlook", edited by F. Binder, L. A. Correa, C. Gogolin, J. Anders, and G. Adesso; comments are most welcome.
I have recently joined the International Editorial Board of the Journal of Physics Communications by IoP. The journal is fully open access and is committed to rigorous peer review assessing the scientific quality and ensuring that contributions advance the respective research areas but explicitly allows for the inclusion of negative or null results and replication studies. 
Read about an exciting new method to transfer quantum information between quantum memories and quantum processors in "Fault-tolerant interface between quantum memories and quantum processors" which was just published in Nat. Commun. 8, 1321 (2017) [arXiv:1609.08062].

Press release from the University of Innsbruck (English)
Austrian news (in German): ORF Tirol & der Standard
Phys.org coverage (English)
IEEE Spectrum Article (English)
In our new experiment & theory collaboration paper [arXiv:1709.07344] we develop efficient new techniques for certifying high-dimensional entanglement using measurements in only two bases. We demonstrate the usefulness of this method by certifying 8-dimensional entanglement of two photons entangled in their orbital angular momentum.
In our new paper entitled "Speeding-up the decision making of a learning agent using an ion trap quantum processor" [Sriarunothai, Wölk, Giri, Friis, Dunjko, Briegel, Wunderlich, arXiv:1709.01366], we report on a proof-of-principle experiment, demonstrating a speed-up in the deliberation time of quantum learning agents w.r.t. to their classical counterparts.
"Geometry of two-qubit states with negative conditional entropy", our recent paper contrasting a variety of different entanglement detection criteria geometrically, has been published in J. Phys. A: Math. Theor. 50, 125301 (2017) [arXiv:1609.04144].

Update: The article is now fully open access.
Our new article on quantum thermodynamics entitled "Passivity and practical work extraction using Gaussian operations" has been published in the New Journal of Physics: New J. Phys. 18, 113028 (2016) [arXiv:1608.04977].

I am going to teach the module "Proseminar Theoretische Quanteninformation" (Proseminar theoretical quantum information) at the University of Innsbruck in the upcoming term.
I am happy to announce that my new perspective article Unlocking fermionic mode entanglement which I was asked to write about the nice paper New J. Phys. 18, 043036 (2016) by Dasenbrook et al., has now been published in New J. Phys. 18, 061001 (2016).
It is my pleasure to announce that the registration for the 2016 Introductory Course on Quantum Information in Innsbruck is now open. The course, held 12-14 July 2016 in Innsbruck is aimed at master's level students and is also suitable for students just finishing their bachelor’s degree and first-year PhD students who have recently joined the field. The registration deadline is 1 June 2016. More information here.
Our new quantum thermodynamics paper "Energetics of correlations in interacting systems" on the energy cost of correlating interacting systems at finite temperatures has been published in Phys. Rev. E 93, 042135 (2016) [arXiv:1511.08654].
My paper on the issues (and their resolution) of constructing a fermionic quantum information theory has been published in New J. Phys. 18, 033014 (2016). Particular thanks to the referees and editors with NJP for their useful comments!
It is my pleasure to announce that our new paper on "Coherent controlization using superconducting qubits" has been published in Sci. Rep. 5, 18036 (2015).
We have found a way to determine the optimal states for estimating small parameters encoded in arbitrary Gaussian transformations in recently published paper: Phys. Rev. A 92, 022106 (2015) [arXiv:1502.07654],
How much can one correlate two systems at a given energy cost? We have found the optimal bounds and the protocols saturating these bounds. Have a look at our latest paper: "The thermodynamics of creating correlations: Limitations and optimal protocols", now published in Phys. Rev. E 91, 032118 (2015)[arXiv:1409.4647].
Our article on implementing decision-making processes of learning agents in ion traps was published in New J. Phys. 17, 023006 (2015) [arXiv:1407.2830].
I feel very honoured to have been invited to give a talk at the Doppler Institute in Prague on the occasion of the award of the Václav Votruba Prize 2014 for the best thesis in theoretical physics.