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Achievements of DK ALM PhD student researchers


 

 

Besides publications in scientific journals and research results, prizes were won and some papers were selected for front pages.

Front Page Covers

Publication highligthed by Editors' Suggestion

Poster Prizes

Awards & Prizes

Participation Lindau Nobel Laurete Meeting

Best student paper award

DK ALM scientific outreach project

 

Front Page Covers

 

 bersenkowitsch_madlener_heller_frontpage

Nina K. Bersenkowitsch, Sarah J. Madlener, Jakob Heller

Nina K. Bersenkowitsch, Sarah J. Madlener, Jakob Heller, Christian van der Linde, Milan Ončák, and Martin K. Beyer

Environ. Sci.: Atmos., 2023, 3, 10, 1396-1406
https://doi.org/10.1039/D3EA00039G


Spectroscopy of cluster aerosol models: IR and UV spectra of hydrated glyoxylate with and without sea salt

 

Abstract:

Glyoxylic acid is formed in the troposphere by oxidation of organic molecules. In sea salt aerosols, it is expected to be present as glyoxylate, integrated into the salt environment and strongly interacting with water molecules. In water, glyoxylate is in equilibrium with its gem-diol form. To understand the influence of water and salt on the photophysics and photochemistry of glyoxylate, we generate small model clusters containing glyoxylate by electrospray ionization and study them by Fourier-Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry. We used infrared multiple photon dissociation spectroscopy and UV/vis photodissociation spectroscopy for structural characterization as well as quantum chemical calculations to model the spectra and dissociation patterns. Resonant absorption of infrared radiation leads to water evaporation, which indicates that water and glyoxylate are separate molecular entities in a significant fraction of the clusters, in line with the observed absorption of UV light in the actinic region. Hydration of glyoxylate leads to a change of the dihedral angle in the CHOCOO.H2O complex, causing a slight redshift of the S1 ← S0 transition. However, the barriers for internal rotation are below 5 kJ mol−1, which explains the broad S1 ← S0 absorption extending from about 320 to 380 nm. Most importantly, hydration hinders dissociation in the S1 state, thus enhancing the quantum yield of fluorescence combined with water evaporation. No C–C bond photolysis is observed, but due to the limited signal-to-noise ratio, it cannot be ruled out. The quantum yield, however, will be relatively low. Fluorescence dominates the photophysics of glyoxylate embedded in the dry salt cluster, but the quantum yield shifts towards internal conversion upon addition of one or two water molecules.

  


 karli_nanoletters_2022_a

Yusuf Karli

Yusuf Karli, Florian Kappe, Vikas Remesh,  Thomas K. Bracht, Julian Münzberg, Saimon Covre da Silva, Tim Seidelmann, Vollrath Martin Axt, Armando Rastelli, Doris E. Reiter, and Gregor Weihs

Nano Lett., 2022, 22, 16, 6567–6572
https://doi.org/10.1021/acs.nanolett.2c01783

 

SUPER Scheme in Action: Experimental Demonstration of Red-Detuned Excitation of a Quantum Emitter

 

Abstract: The quest for the perfect single-photon source includes finding the optimal protocol for exciting the quantum emitter. Coherent optical excitation was, up until now, achieved by tuning the laser pulses to the transition frequency of the emitter, either directly or in average. Recently, it was theoretically discovered that an excitation with two red-detuned pulses is also possible where neither of which would yield a significant upper-level population individually. We show that the so-called swing-up of quantum emitter population (SUPER) scheme can be implemented experimentally with similar properties to existing schemes by precise amplitude shaping of a broadband pulse. Because of its truly off-resonant nature, this scheme has the prospect of powering high-purity photon sources with superior photon count rate.

 

 

 zanner_nature_may2022_cover

Maximilian Zanner

Maximilian Zanner, Tuure Orell, Christian M.F. Schneider, Romain Albert, Stefan Oleschko, Mathieu L. Juan, Matti Silveri and Gerhard Kirchmair

Nature Physics, 2022, volume 18, pages 538–543
https://www.nature.com/articles/s41567-022-01527-w

 

Coherent control of a multi-qubit dark state in waveguide quantum electrodynamics

 

Abstract: Superconducting qubits in a waveguide have long-range interactions mediated by photons that cause the emergence of collective states. Destructive interference between the qubits decouples the collective dark states from the waveguide environment. Their inability to emit photons into the waveguide render dark states a valuable resource for preparing long-lived quantum many-body states and realizing quantum information protocols in open quantum systems. However, they also decouple from fields that drive the waveguide, making manipulation a challenge. Here we show the coherent control of a collective dark state that is realized by controlling the interactions between four superconducting transmon qubits and local drives. The dark state’s protection against decoherence results in decay times that exceed those of the waveguide-limited single qubits by more than two orders of magnitude. Moreover, we perform a phase-sensitive spectroscopy of the two-excitation manifold and reveal bosonic many-body statistics in the transmon array. Our dark-state qubit provides a starting point for implementing quantum information protocols with collective states.

  

 

 Heller_pccp2022

Jakob Heller

Jakob Heller, Ethan M. Cunningham, Jessica C. Hartmann, Christian van der Linde, Milan Ončák, and Martin K. Beyer

Phys. Chem. Chem. Phys., 2022, 24, 14699-14708
https://doi.org/10.1039/D2CP00833E

 

Size-dependent H and H2 formation by infrared multiple photon dissociation spectroscopy of hydrated vanadium cations, V+(H2O)n, n = 3–51


 

Abstract: Infrared spectra of the hydrated vanadium cation (V+(H2O)n; n = 3–51) were measured in the O–H stretching region employing infrared multiple photon dissociation (IRMPD) spectroscopy. Spectral fingerprints, along with size-dependent fragmentation channels, were observed and rationalized by comparing to spectra simulated using density functional theory. Photodissociation leading to water loss was found for cluster sizes n = 3–7, consistent with isomers featuring intact water ligands. Loss of molecular hydrogen was observed as a weak channel starting at n = 8, indicating the advent of inserted isomers, HVOH+(H2O)n−1. The majority of ions for n = 8, however, are composed of two-dimensional intact isomers, concordant with previous infrared studies on hydrated vanadium. A third channel, loss of atomic hydrogen, is observed weakly for n = 9–11, coinciding with the point at which the H and H2O calculated binding energies become energetically competitive for intact isomers. A clear and sudden spectral pattern and fragmentation channel intensity at n = 12 suggest a structural change to inserted isomers. The H2 channel intensity decreases sharply and is not observed for n = 20 and 25–51. IRMPD spectra for clusters sizes n = 15–51 are qualitatively similar indicating no significant structural changes, and are thought to be composed of inserted isomers, consistent with recent electronic spectroscopy experiments.

 

 

 heller_beyer_2021

Jakob Heller

Jakob Heller, Tobias F. Pascher, Dominik Muß, Christian van der Linde, Martin K. Beyer, and Milan Ončák

Phys. Chem. Chem. Phys., 2021, 23, 22251-22262
 
 
Spectroscopy of hydrated vanadium cations, V+ (H2O)n, n = 1–41, a   model system for photochemical hydrogen evolution

 

Abstract: Photochemical hydrogen evolution provides fascinating perspectives for light harvesting. Hydrated metal ions in the gas phase are ideal model systems to study elementary steps of this reaction on a molecular level. Here we investigate mass-selected hydrated monovalent vanadium ions, with a hydration shell ranging from 1 to 41 water molecules, by photodissociation spectroscopy. The most intense absorption bands correspond to 3d–4p transitions, which shift to the red from n = 1 to n = 4, corresponding to the evolution of a square-planar complex. Additional water molecules no longer interact directly with the metal center, and no strong systematic shift is observed in larger clusters. Evolution of atomic and molecular hydrogen competes with loss of water molecules for all V+(H2O)n, n ≤ 12. For n ≥ 15, no absorptions are observed, which indicates that the cluster ensemble is fully converted to HVOH+(H2O)n−1. For the smallest clusters, the electronic transitions are modeled using multireference methods with spin–orbit coupling. A large number of quintet and triplet states is accessible, which explains the broad features observed in the experiment. Water loss most likely occurs after a series of intersystem crossings and internal conversions to the electronic ground state or a low-lying quintet state, while hydrogen evolution is favored in low lying triplet states.

 

 

 dahlmann_dez2021_aip

Franziska Dahlmann

Franziska Dahlmann, Christine Lochmann, Aravingh N. Marimuthu, Miguel Lara-Moreno, Thierry Stoecklin, Philippe Halvick, Maurice Raoult, Olivier Dulieu, Robert Wild, Stephan Schlemmer, Sandra Brünken, and Roland Wester

 J. Chem. Phys., 2021, 155, 241101
https://doi.org/10.1063/5.0073749

 

Strong ortho/para effects in the vibrational spectrum of Cl(H2)

 

Abstract: The predissociation spectrum of the 35Cl-(H2) complex is measured between 450 and 800 cm−1 in a multipole radiofrequency ion trap at different temperatures using the FELIX infrared free electron laser. Above a certain temperature, the removal of the Cl(p-H2) para nuclear spin isomer by ligand exchange to the Cl(o-H2) ortho isomer is suppressed effectively, thereby making it possible to detect the spectrum of this more weakly bound complex. At trap temperatures of 30.5 and 41.5 K, we detect two vibrational bands of Cl(p-H2) at 510(1) and 606(1) cm−1. Using accurate quantum calculations, these bands are assigned to transitions to the inter-monomer vibrational modes (v1, v2l2) = (0, 20) and (1, 20), respectively.

  

 

 unnikrishnan_prlv125i13

Govind Unnikrishnan

Tsz-Him Leung, Malte N. Schwarz, Shao-Wen Chang, Charles D. Brown, Govind Unnikrishnan, and Dan Stamper-Kurn

Phys. Rev. Lett., 2021, 125, 133001
https://doi.org/10.1063/5.0049320

 

Interaction-Enhanced Group Velocity of Bosons in the Flat Band of an Optical Kagome Lattice


 

Abstract: Geometric frustration of particle motion in a kagome lattice causes the single-particle band structure to have a flat s-orbital band. We probe this band structure by placing a Bose-Einstein condensate into excited Bloch states of an optical kagome lattice, and then measuring the group velocity through the atomic momentum distribution. We find that interactions renormalize the band structure, greatly increasing the dispersion of the third band, which is nearly non-dispersing the single-particle treatment. Calculations based on the lattice Gross-Pitaevskii equation indicate that band structure renormalization is caused by the distortion of the overall lattice potential away from the kagome geometry by interactions.

 

  

 heller_chem202103992-toc-0001-m

Jakob Heller

Jakob Heller, Tobias F. Pascher, Christian van der Linde, Milan Ončák, and Martin K. Beyer

Chem. Eur. J., 2021, 66
 
 
Photochemical Hydrogen Evolution at Metal Centers Probed with Hydrated Aluminium Cations, Al+(H2O)n, n=1–10

 

Abstract: More complex than expected: Photochemical hydrogen evolution in Al+(H2O)n involves conical intersections, multiple intersystem crossings between singlet and triplet surfaces, and electron transfer. Three neutral photoproducts are observed—hydrogen atoms, hydrogen molecules, and water. For the Al+(H2O)2 cluster, we show how a hydrogen radical is ejected and dictates reactivity. Our results underline the multitude of pathways in photochemistry of these seemingly simple ions.

 

Publication highlighted as an Editors’ Suggestion

 

 Goschin_Northup_PRL_02_2024

 

Florian Goschin

Lorenzo Dania, Dmitry S. Bykov, Florian Goschin, Markus Teller, Abderrahmane Kassid, Tracy E. Northup

Phys. Rev. Lett. 132, 133602
https://doi.org/10.1103/PhysRevLett.132.133602

Ultrahigh Quality Factor of a Levitated Nanomechanical Oscillator

Paper is featured in physics and editors' suggestion.

 

Abstract:

A nanoresonator trapped in ultrahigh vacuum features an exceptionally high quality factor, showing promise for applications in force sensors and macroscopic tests of quantum mechanics.

A levitated nanomechanical oscillator under ultrahigh vacuum is highly isolated from its environment. It has been predicted that this isolation leads to very low mechanical dissipation rates. However, a gap persists between predictions and experimental data. Here, we levitate a silica nanoparticle in a linear Paul trap at room temperature, at pressures as low as 7×1011mbar. We measure a dissipation rate of 2π×69(22)nHz, corresponding to a quality factor exceeding 1010, more than 2 orders of magnitude higher than previously shown. A study of the pressure dependence of the particle’s damping and heating rates provides insight into the relevant dissipation mechanisms.

Poster Prizes

 

 2034 Wessmayer_DPG_cnoy2023_Wessmayer_dpg_distances

 

David Weßmayer / David Wessmayer

David Wessmayer, Norbert Przybilla, Keith Butler

Contribution submission to the conference SMuK 2023

Quantitative spectroscopy of B-type supergiants

The young scientists poster award of the AEF/DPG section Extraterrestrial physics (EP) at the DPG Spring Meeting 2023.

 

Abstract: B-type supergiants are a resourceful tool in adressing various astrophysical questions concerning stellar atmospheres, stellar and galactic evolution and the cosmic distance scale. To facilitate a comprehensive analysis of these objects we assess the applicability of a hybrid non-LTE approach, in which line-blanketed model atmospheres computed under the assumptions of local thermodynamic equilibrium (LTE) are combined with non-LTE line-formation calculations. High-resolution Echelle spectra – constituting an observational sample of 14 Galactic B-type supergiants with masses below about 30 𝑀 – serve as the basis of this investigation. The results of the analysis, including atmospheric and fundamental stellar parameters, multi-species abundances and derived spectroscopic distances, are probed via multiple checks of consistency. Finally, we also test the employed methodology for analyses of intermediate-resolution spectra of extragalactic B-type supergiants.

 

 Dasarath Swaraj 2023

 

Dasarath Swaraj

Dasarth Swaraj, Jerin Judy, Tim Michaelsen, Fabio Zappa, Arnab Khan, Robert Wild and Roland Wester

799. WE-Heraeus-Seminar on Laboratory Astrophyiscs
September 2023, Heidelberg, DE

 

Simulated H3+ product ion distribution for assumed isotropic scattering and vibrational state population according to degeneracy


 

Abstract: Crossed-beam reactive scattering experiments offer a detailed understanding of the dynamics involved in elementary reactions occurring in the gas phase. By employing velocity map imaging (VMI), it is possible to acquire angle and energy differential cross-sections, as demonstrated in previous studies. In this study, we present a comprehensive design plan and relevant simulations for an experimental setup intended to investigate ion-molecule reactions with enhanced precision to achieve stateto-state resolution for ion-molecule reactions.
Initially, we are concentrating on the experimental studies on the ion-molecule reaction H2+ + H2 → H3+ + H. Additionally, Monte
Carlo simulations were conducted to determine the expected resolution of the product energy for the reaction. To generate H₂⁺
ions, we employ laser-induced ionization of H₂ using the 3rd or 4th harmonic of a pulsed Nd:YAG laser, ensuring that the ions
primarily occupy the vibrational ground state. The ion beam is then overlapped with a beam of neutral molecules, and the
resulting collision products are collected and analyzed using the VMI spectrometer. Furthermore, we plan to implement
coincidence detection to simultaneously observe both the ionic and neutral products subsequent to the reaction.

 

 Dahlmann_posterprize2022

 

Franziska Dahlmann

Franziska Dahlmann, Christine Lochmann, Aravindh N. Marimuthu, Miguel Lara-Moreno, Thierry Stoecklin, Philippe Halvick, Maurice Raoult, Olivier Dulieu, Robert Wild, Stephan Schlemmer, Sandra Brünken and Roland Wester

739. WE-Heraeus-Seminar on Molecular Physics and Physical Chemistry with Advanced Photon Sources
January 2022, Bad Honnef, DE

 

Strong ortho/para effects in the vibrational spectrum of Cl-(H2)


 

Abstract: The predissociation spectrum of the 35Cl-(H2) complex is measured between 450 and 800 cm-1 in a multipole radiofrequency ion trap at different temperatures using the FELIX infrared free electron laser. Above a certain temperature, the removal of the Cl-(para-H2) para nuclear spin isomer by ligand exchange to the Cl-(ortho-H2) ortho isomer is suppressed effectively, thereby making it possible to detect the spectrum of this more weakly bound complex. At trap temperatures of 30.5 and 41.5 K, we detect two vibrational bands of Cl-(para-H2) at 510(1) and 606(1) cm-1. Using accurate quantum calculations, these bands are assigned to transitions to the inter-monomer vibrational modes (ν1, ν2, l2) = (0, 2, 0 ) and (1, 2, 0), respectively.

 

 

 Poster Prize Scheil 2022


Verena Scheil

Verena Scheil, Raphael Holzinger, Maria Moreno-Cardoner, and Helmut Ritsch

71th annual meeting of the ÖPG

 

Optical Properties of Nanoscopic Double-Rings of Quantum Emitters


 

Abstract: A single ring of sub-wavelength spaced dipole-coupled quantum emitters can exhibit very special optical features, in contrast to a one-dimensional chain of emitters. This includes the emergence of extremely subradiant collective eigenmodes whose lifetime increases exponentially with the atom number, and the existence of optical modes acting as those of an optical resonator.
Motivated by structures commonly appearing in natural light harvesting complexes we extend these studies to strongly coupled rings geometries. We find that a spin wave ansatz properly describes the radiation properties of double-ring structures, allowing us to study the rich behavior of superradiance and subradiance in these systems. We further proceed to analyze the collective eigenmodes of realistic light harvesting complexes in purple bacteria which share a similar coupled ring structure.  These findings can be relevant in the context of excitation energy transport in both natural and artificial light harvesting complexes.

 

 

 Englbrecht Matthias Posterprize

Matthias Englbrecht

Matthias Englbrecht, Tristan Kraft, and Barbara Kraus

Conference Entanglement in Action, Benasque Spain

 

Party-local Clifford transformations of stabilizer states

 

Abstract: Stabilizer states and graph states find application in quantum error correction, measurement-based quantum computation and various other concepts in quantum information theory. In this work, we study party-local Clifford (PLC) transformations among stabilizer states. These transformations arise as a physically motivated extension of local operations in quantum networks with access to bipartite entanglement between some of the nodes of the network. First, we show that PLC transformations among graph states are equivalent to a generalization of the well-known local complementation, which describes local Clifford transformations among graph states. Then, we introduce a new mathematical framework to study PLC equivalence of stabilizer states. This framework allows us to study decompositions of stabilizer states into tensor products of indecomposable ones, that is, decompositions into states from the entanglement generating set (EGS). While the EGS is finite up to 3 parties [Bravyi et al., J. Math. Phys. 47, 062106 (2006)], we show that for 4 and more parties it is an infinite set. Finally, we generalize the framework to qudit stabilizer states in prime dimensions not equal to 2, which allows us to show that qudit stabilizer states decompose uniquely into states from the EGS.

 

 

 

 2022_Karli

Yusuf Karli

Yusuf Karli, Florian Kappe, Vikas Remesh,  Thomas K. Bracht, Julian Münzberg, Saimon Covre da Silva, Tim Seidelmann, Vollrath Martin Axt, Armando Rastelli, Doris E. Reiter, and Gregor Weihs

Photonic Quantum Technologies – A Revolution in Communication, Sensing, and Metrology
March 2022, Bad Honnef, DE

 

SUPER Scheme in Action: Experimental Demonstration of Red-detuned Excitation of a Quantum Dot

 

Abstract: The quest for the perfect single-photon source includes finding the optimal protocol for exciting the quantum emitter. Based on a recently proposed, so-called SUPER (swing-up of quantum emitter population) scheme, we demonstrate experimentally that two red-detuned laser pulses, neither of which could yield a significant upper-level population individually, lead to the coherent excitation of a semiconductor quantum dot. We characterize the emitted single photons and show that they have properties comparable to those achieved under resonant excitation schemes.


 

 

 2022_salzburger_posterprize

Magdalena Salzburger

Magdalena Salzburger, Milan Ončák, Christian van der Linde, and Martin K. Beyer

Unimolecular reaction Faraday Discussion
June 2022, Oxford, UK

 

A simplified multiple-well approach for the master equation modeling of blackbody infrared radiative dissociation (BIRD) of hydrated carbonate radical anions

 

Abstract: Molecular clusters CO3●‑(H2O)1,2 are found in the lower region of the ionosphere and in the troposphere. Investigation of their properties can be helpful to understand atmospheric chemistry. In this work, we analyze blackbody infrared radiative dissociation (BIRD) of singly and doubly hydrated carbonate radical anion clusters at different temperatures.
The molecular clusters are generated with a laser vaporisation source and guided to a Fourier Transformation Ion Cyclotron Resonance Mass Spectrometer (FT-ICR-MS). The temperature of the ICR-Cell can be regulated by a variable supply of liquid nitrogen or warm water.
We observe loss of water from CO3●‑(H2O)1,2 clusters. BIRD‑kinetics were measured for temperatures between 210 and 350 K. Dissociation kinetics are first order, and are fitted with a genetic algorithm to obtain unimolecular rate constants. The kinetics exhibit apparent Arrhenius behavior. Master equation modeling of the temperature dependent kinetics is performed, taking into account all low-lying isomers that are populated at the experimental temperatures. Densities of states calculated with the Beyer-Swinehart algorithm are compared with ab initio molecular dynamics simulations. Modeling yields binding energies, which are compared with quantum chemical calculations on the CCSD/aug-cc-pVDZ level of theory.

  

 

 Reider_posterprize2022


Anna Maria Reider

Anna Maria Reider, Felix Laimer, Fabio Zappa, Michael Gatchell, and Paul Scheier

14th International Conference on Quantum Fluid Clusters
April 2022, Erice, IT

 

Multiply Charged Superfluid Helium Droplets

 

Abstract: The poster presents our experimental approaches and the results that prove the existence of multiply charged anionic and cationic superfluid helium droplets. Anionic helium droplets carrying up to five charges and cations exceeding 50+ charge centres can be identified in the data and scaling laws for the distribution of the charge centres with the helium droplets are discussed.

 

 

 2018_yao

Maximilian Sohmen

24th YAO conference
June 2018, Glasgow, UK

 

Versatile Experiment for ultracold Erbium, Dysprosium, and their Mixture

 

 

 

 

 hebenstreit_poster_2018

 

 

Martin Hebenstreit

Distinguished poster prize

Centro de Ciencias de Benasque Pedro Pascual

Multipartite Entanglement Workshop, Benasque, 2018


 

 

 Awards & Prizes

   

 Hauptuni

 
Jozef Joachim Arfor Houwman

Early Stage Funding grant, Universität Innsbruck

STORMiEr: Stochastic Optical Reconstruction Microscopy in Erbium


 

Abstract: Lattice models have been powerful tools to describe physical phenomena and can studied using many different platforms. One such platforms are atoms cooled to quantum degeneracy and confined in optical lattices. Using our atomic species, Erbium, some exotic phenomena are predicted to occur when the lattice parameter is very small, or to put it in other words, when the particles are very close to each other. However, at such small distances it becomes hard or even impossible to image the individual particles using conventional techniques. Adapting an advanced imaging technique from the field of molecular biology called superresolution to our system might allow us to circumvent this standard optical limit.

About Early Stage Funding grant, Universität Innsbruck: The aim of the programme is to carry out an independent, small research project at the beginning of an academic career. Doctoral candidates and graduates of doctoral programmes whose doctoral or PhD degree was awarded no longer than 2 years ago (date of the official notification). Child-rearing periods (two years for each child cared for), care periods (usually care leave) and longer periods of serious illness that have led to a career interruption are taken into account. It must be ensured that the project leader has an active employment relationship with the University of Innsbruck for the entire duration of the project.

  

zanner_thesisaward_iqoqi_2023

Maximillian Zanner, group Gerhard Kirchmair

Thesis award, IQOQI

Coherent Control of Multi-Qubit Dark States in Waveguide Quantum Electrodynamics


 

Abstract:  In his dissertation submitted in 2022, Maximilian Zanner explores how quantum states can be protected from the environment in order to create long-lived quantum memories. This is achieved by exploiting the interaction between multiple qubits which yields the emergence of so-called dark states. In contrast to the single qubit states, these dark states decouple from the environment and thus cannot decay to the ground state, effectively extending the lifetime of the excited state. However, the long-lived nature of the dark state comes at the cost of losing the ability of coherent control. The results show that by extending the experimental system, it is possible to regain control over the dark state and use it as a manipulatable quantum information storage. This paves the way for investigating quantum many-body systems in dissipative environments as well as creating communication channels between two physically separated quantum computers.

Award for outstanding achievements - Österreichische Akademie der Wissenschchaften, ÖAW / Institute for Quantum Optics and Quantum Information, IQOQI:  The IQOQI Thesis Award is presented to promising young physicists at the Institute of Quantum Optics and Quantum Information in Innsbruck for their outstanding achievements in the field of quantum physics. Endowed with a prize money of 1,000 Euros, it recognizes excellent research of graduates of PhD or doctoral studies at the University of Innsbruck.

 

 poulsen_kanada_2019

Hendrik Poulsen-Nautrup

David Sauerwein, Nolan R. Wallach, Gilad Gour, and Barbara Kraus

Quantum. The Open Journal for Quantum Science 3, No. 142
https://quantum-journal.org/papers/q-2019-05-20-142/

Computationally Universal Phase of Quantum Matter /
Subsystem Symmetries, Quantum Cellular Automata,
and Computational Phases of Quantum Matter

Thanksgiving 2019

Zentrum für Kanadastudien an der Universität Innsbruck
Canadian Studies Centre - Centre d‘études canadiennes

Abstract:

Quantum phases of matter are resources for notions of quantum computation. In this work, we establish a new link between concepts of quantum information theory and condensed matter physics by presenting a unified understanding of symmetry-protected topological (SPT) order protected by subsystem symmetries and its relation to measurement-based quantum computation (MBQC). The key unifying ingredient is the concept of quantum cellular automata (QCA) which we use to define subsystem symmetries acting on rigid lower-dimensional lines or fractals on a 2D lattice. Notably, both types of symmetries are treated equivalently in our framework. We show that states within a non-trivial SPT phase protected by these symmetries are indicated by the presence of the same QCA in a tensor network representation of the state, thereby characterizing the structure of entanglement that is uniformly present throughout these phases. By also formulating schemes of MBQC based on these QCA, we are able to prove that most of the phases we construct are computationally universal phases of matter, in which every state is a resource for universal MBQC. Interestingly, our approach allows us to construct computational phases which have practical advantages over previous examples, including a computational speedup. The significance of the approach stems from constructing novel computationally universal phases of matter and showcasing the power of tensor networks and quantum information theory in classifying subsystem SPT order.

About Canada Award: Since the end of the 20th century the Canadian Studies Centre of the University of Innsbruck has been celebrating the "scientific harvest" of the current year with a special event in November, framed by music and lectures and recalling the North American "Thanksgiving" celebrations. This event is meant to present and honor promising young scholars of the University of Innsbruck who have dealt with Canadian Studies topics in their scientific work (thesis, article) or have collaborated with Canadian scholars.

 

 2019_cozzarelli_briegel

 

Hendrik Poulsen-Nautrup

Alexey A. Melnikov, Hendrik Poulsen Nautrup, Mario Krenn, Vedran Dunjko, Markus Tiersch, Anton Zeilinger, and Hans J. Briegel

PNAS,  115 (6) 1221-1226
https://www.pnas.org/doi/10.1073/pnas.1714936115

Active learning machine learns to create new quantum experiments

Class I: Physical and Mathematical Sciences

The 2018 Cozzarelli Prize was awarded at the 156th Annual Meeting of the National Academy of Sciences in April 2019 in Washington, DC.

 

Abstract:  Modern experiments in quantum physics have advanced researchers’ understanding of several fundamental concepts of quantum theory. However, further advances in quantum physics are likely to require complex experiments that are challenging to design and potentially counterintuitive. Melnikov, Poulsen Nautrup, et al. developed an artificial intelligence system capable of designing experiments for producing complex entangled photon states, which are difficult to realize experimentally. The system learned to design the desired experiments more efficiently than previous approaches, discovering nonstandard experimental techniques in the process. The work expands the possibilities for the role of machines in scientific research.

About Cozzarelli Prize: The Cozzarelli Prize is awarded annually to six research teams whose PNAS articles have made outstanding contributions to their field. Each team represents one of the six classes of the National Academy of Sciences (NAS): Physical and Mathematical Sciences; Biological Sciences; Engineering and Applied Sciences; Biomedical Sciences; Behavioral and Social Sciences; and Applied Biological, Agricultural, and Environmental Sciences.

 

 sauerwein_kraus_kanadazentrum_2018

David Sauerwein

David Sauerwein, Nolan R. Wallach, Gilad Gour, and Barbara Kraus

Phys. Rev. X 8, 031020
https://doi.org/10.1103/PhysRevX.8.031020

Transformations among Pure Multipartite Entangled States via Local Operations are Almost Never Possible

1st Prize for David Sauerwein - Thanksgiving 2018

Zentrum für Kanadastudien an der Universität Innsbruck
Canadian Studies Centre - Centre d‘études canadiennes

Abstract:  Local operations assisted by classical communication (LOCC) constitute the free operations in entanglement theory. Hence, the determination of LOCC transformations is crucial for the understanding of entanglement. We characterize here almost all LOCC transformations among pure multipartite multilevel states. Combined with the analogous results for qubit states shown by Gour et al. [J. Math. Phys. (N.Y.) 58, 092204 (2017)], this gives a characterization of almost all local transformations among multipartite pure states. We show that nontrivial LOCC transformations among generic, fully entangled, pure states are almost never possible. Thus, almost all multipartite states are isolated. They can neither be deterministically obtained from local-unitary-inequivalent (LU-inequivalent) states via local operations, nor can they be deterministically transformed to pure, fully entangled LU-inequivalent states. In order to derive this result, we prove a more general statement, namely, that, generically, a state possesses no nontrivial local symmetry. We discuss further consequences of this result for the characterization of optimal, probabilistic single-copy and probabilistic multicopy LOCC transformations and the characterization of LU-equivalence classes of multipartite pure states.

About Canada Award: Since the end of the 20th century the Canadian Studies Centre of the University of Innsbruck has been celebrating the "scientific harvest" of the current year with a special event in November, framed by music and lectures and recalling the North American "Thanksgiving" celebrations. This event is meant to present and honor promising young scholars of the University of Innsbruck who have dealt with Canadian Studies topics in their scientific work (thesis, article) or have collaborated with Canadian scholars.

Participation and panel discussion member at 73rd Lindau Nobel Laurete Meeting

 

 73rdlindaumeeting_panel

 

Yusuf Karli

Panel discussion:
Nobel laureate Anton Zeilinger (2022)
Nobel laureate Serge Haroche (2012)
Stern-Gerlach award-winner Rainer Blatt (2012)
DK ALM PhD student Yusuf Karli

Moderator: Markus Arndt
From Quantum Foundations To Emerging Quantum Technologies


 

Every year since the 1950s, there has been one Lindau Meeting, which focuses on physics again in 2024. The 73rd Lindau Nobel Laureate Meeting is a 5-day event featuring conferences, attended by about 30-40 Nobel Laureates in Physics and 600 young scientists from all over the world. The selection process is twofold. Firstly, one needs to apply to the Science Academy of their residing country to be nominated for Lindau.

Our DK ALM Phd student researcher Yusuf Karli, PhD student of Gregor Weihs, applied to the Austrian Science Academy (FWF) in September 2023 and was selected as one of Austria's 11 candidates. All the selected nominations underwent another selection process conducted by the Lindau Nobel Meeting and Yusuf was chosen as one of the 650 young scientists from around the world to take part including a given talk at the Lindau Nobel Laurente Meeting 2024.

 Yusuf has also been invited for a panel discussion / partner event on July 1st 2024 which meant he shared the podium with Anton Zeilinger, Nobel Laurate 2022, Serge Haroche, Nobel Laurate 2012, Rainer Blatt, Stern-Gerlach award-winner 2012 and the moderator Markus Arndt. The meeting was opened by the Austrian Minister of Education, Science and Research, Martin Polaschek.

Best student paper award, Universität Innsbruck

To promote young academics and acknowledge their achievements, the University of Innsbruck announcing the "Best Student Paper Award" every year. A total of at least 6,000 euros will be awarded.

   

 poli_beststudentpaper_2024

Elena Poli

Glitches in Rotating Supersolids

Elena Poli, Thomas Bland, Samuel J. M. White, Manfred J. Mark, Francesca Ferlaino, Silvia Trabucco, and Massimo Mannarelli

Phys. Rev. Lett. 131, 223401 – Published 29 November 2023

https://doi.org/10.1103/PhysRevLett.131.223401

Paper was done in collaboration with the group of Massimo Mannarelli in L’Aquila, that Elena visited last year thanks to the DK ALM funding.

 

Abstract:  Glitches, spin-up events in neutron stars, are of prime interest, as they reveal properties of nuclear matter at subnuclear densities. We numerically investigate the glitch mechanism due to vortex unpinning using analogies between neutron stars and dipolar supersolids. We explore the vortex and crystal dynamics during a glitch and its dependence on the supersolid quality, providing a tool to study glitches from different radial depths of a neutron star. Benchmarking our theory against neutron-star observations, our work will open a new avenue for the quantum simulation of stellar objects from Earth.

 

 salzburger_beststudentspaper_2022

Salzburger Magdalena

Simplified multiple-well approach for the master equation modeling of blackbody infrared radiative dissociation of hydrated carbonate radical anions


Magdalena Salzburger, Milan Ončák, Christian van der Linde, Marting Klemens Beyer

J. Am. Chem. Soc. 2022, 144, 21485−21493

 https://doi.org/10.1021/jacs.2c07060

 

Abstract:  Blackbody infrared radiative dissociation (BIRD) in a collision-free environment is a powerful method for the experimental determination of bond dissociation energies. In this work, we investigate temperature-dependent BIRD of CO3·–(H2O)1,2 at 250–330 K to determine water binding energies and assess the influence of multiple isomers on the dissociation kinetics. The ions are trapped in a Fourier-transform ion cyclotron resonance mass spectrometer, mass selected, and their BIRD kinetics are recorded at varying temperatures. Experimental BIRD rates as a function of temperature are fitted with rates obtained from master equation modeling (MEM), using the water binding energy as a fit parameter. MEM accounts for the absorption and emission of photons from black-body radiation, described with harmonic frequencies and infrared intensities from quantum chemical calculations. The dissociation rates as a function of internal energy are calculated by Rice–Ramsperger–Kassel–Marcus theory. Both single-well and multiple-well MEM approaches are used. Dissociation energies derived in this way from the experimental data are 56 ± 6 and 45 ± 3 kJ/mol for the first and second water molecules, respectively. They agree within error limits with the ones predicted by ab initio calculations done at the CCSD(T)/aug-cc-pVQZ//CCSD/aug-cc-pVDZ level of theory. We show that the multiple-well MEM approach described here yields superior results in systems with several low-lying minima, which is the typical situation for hydrated ions.

DK ALM scientific outreach project

 

 21-07-seeker-dk

 

Hendrik Poulsen-Nautrup, Lea Trenkwalder

Fulvio Flamini, Hendrik Poulsen-Nautrup, Lea Trenkwalder (alphabethical order)

Seeker – A trading card game for outreach in science

Seeker has been sponsored by DK ALM trough the funding of the FWF, W1259-N27, and the Förderkreis 1669 at the University of Innsbruck. (https://www.uibk.ac.at/de/foerderkreis1669/)

 

Abstract:  Science education has become progressively more central at a European level, as exemplified by the efforts put forth by the Horizon 2020 Work Programme. In this direction, the team aims to develop a trading card game – Seeker – which fully incarnates the attitudinal, cognitive and social objectives that are usually associated with outreach. Their ambitious project holds the potential to bring young generations closer to science.

As physicists, the team believes being scientists is both a privilege and a responsibility towards society. They believe that, while pursuing the truth according to the ethics standards, substantial effort should be devoted in shortening the distance from the general public. In the long term, this has concrete, practical  consequences for science itself: raising science literacy increases the potential of the youngest generation, increases trust in scientists and enables a more efficient diffusion of results, among others. Hence, while their professional career is dedicated to advancing science, they are also driven by the wish to further enhance it, and, with it, to enhance society. Seeker allows them to make a step in this direction, by using a medium we are all familiar with: a trading card game and the power of internet.

 


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