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Non-perturbative aspects of strongly interacting quantum field theories

English title Non-perturbative aspects of strongly interacting quantum field theories
Applicant Wenger Urs Rudolf
Number 149331
Funding scheme Project funding
Research institution Institut für Theoretische Physik Universität Bern
Institution of higher education University of Berne - BE
Main discipline Theoretical Physics
Start/End 01.10.2014 - 30.04.2016
Approved amount 227'000.00
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All Disciplines (2)

Discipline
Theoretical Physics
Particle Physics

Keywords (8)

nonperturbative methods; supersymmetry breaking; quantum statistical mechanics; chiral symmetry breaking; supersymmetric Yang-Mills quantum mechanics; chiral perturbation theory; lattice QCD calculations; thermodynamics of black holes

Lay Summary (German)

Lead
In der Elementarteilchenphysik spielen nicht-störungstheoretische Phänomene eine wichtige, wenn nicht häufig sogar eine entscheidende Rolle. Die Quantenfeldtheorie, welche die starke Wechselwirkung zwischen den Elementarteilchen beschreibt, die sogenannte Quantenchromodynamik (QCD), zeigt bei tiefen Energien zum Beispiel eine spontane Brechung der chiralen Symmetrie sowie das sogenannte 'Confinement', welches dafür verantwortlich ist, dass nur gebundene, farbneutrale Teilchen, sogenannte Hadronen, in der Natur beobachtet werden können. Die spontane Symmetriebrechung andererseits führt direkt auf das spezielle, in der Natur beobachtete Spektrum der leichtesten Hadronen. Ein qualitatives und quantitatives Verständnis solcher nicht-störungstheoretischer Aspekte von Quantenfeldtheorien sind von äusserster Wichtigkeit für eine Bergündung der zugrunde liegenden, fundamentalen Theorien.
Lay summary

Die Wichtigkeit eines tiefen Verständnisses von Quantenfeldtheorien betrifft insbesondere die QCD und ihre Rechtfertigung als Theorie der starken Wechselwirkung innerhalb des Standardmodells (SM) der Elementarteilchen, aber auch andere stark wechselwirkende Theorien, welche über das SM hinausgehen. In diesem Sinne beinhaltet dieses Projekt zwei Forschungsrichtungen, beide im Kontext nicht-störungstheoretischer Rechnungen in stark wechselwirkenden Quantenfeldtheorien:

a) Die erste Richtung betrifft die quantitative Bestimmung der tief-energetischen Eigenschaften der QCD mithilfe von Computersimulationen. Präzise ab-initio Rechnungen mit realistischen Parametern erlauben eine weitere Reduktion und Kontrolle der systematischen Fehlern, welche in solchen Rechnungen zwangsläufig auftreten, sowie eine weitere Bestätigung der theoretischen Grundlagen. Eine der Herausforderungen liegt zum Beispiel in der genauen Bestimmung von hadronischen Matrixelementen und Formfaktoren, welche in vielen Fällen die Hauptquelle für Unsicherheiten im direkten Vergleich der Theorie mit dem Experiment darstellen. Die Reduktion der Fehler erlaubt eine noch strengere und präzisere Überprüfung des SM und stellt somit einen wertvollen Beitrag zur möglichen Entdeckung neuer Physik ausserhalb des SM dar.

b) Die zweite Richtung betrifft die nicht-störungstheoretische Untersuchung von stark wechselwirkenden, supersymmetrischen (SUSY) Quantenfeldtheorien in tiefen Dimensionen.  Unsere neuesten Entwicklungen solche supersymmetrischen Theorien extrem effizient zu simulieren heben die Untersuchungen auf eine beispiellose, neue Stufe der Genauigkeit. Solche quantitativen Resultate sind zum Beispiel wichtig für das Verständnis gewisser Aspekte der Dualität zwischen Eich- und Gravitationstheorien in höheren Dimensionen und können auch zum besseren Verständnis spezieller Eigenschaften von schwarzen Löchern beitragen. 

Direct link to Lay Summary Last update: 21.08.2014

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
First physics results at the physical pion mass from Nf=2 Wilson twisted mass fermions at maximal twist
Abdel-Rehim A., Alexandrou C., Burger F., Constantinou M., Dimopoulos P., Frezzotti R., Hadjiyiannakou K., Helmes C., Jansen K., Jost C., Kallidonis C., Knippschild B., Kostrzewa B., Koutsou G., Liu L., Mangin-Brinet M., Ottnad K., Petschlies M., Pientka G., Rossi G. C., Urbach C., Wenger U., Werner M. (2017), First physics results at the physical pion mass from Nf=2 Wilson twisted mass fermions at maximal twist, in Physical Review D, 95(9), 094515-094515.
From Spin Models to Lattice QCD – the Scientific Legacy of Peter Hasenfratz
Wenger Urs (ed.) (2017), From Spin Models to Lattice QCD – the Scientific Legacy of Peter Hasenfratz, Proceedings of Science, Trieste (Italy).
An Improved Single-Plaquette Gauge Action
Banerjee Debasish, Bögli Michael, Holland Kieran, Niedermayer Ferenc, Pepe Michele, Wenger Urs, Wiese Uwe-Jens, Banerjee Debasish, Bögli Michael, Holland Kieran, Niedermayer Ferenc, Pepe Michele, Wenger Urs, Wiese Uwe-Jens (2016), An Improved Single-Plaquette Gauge Action, in JHEP, 03, 116-116.
Comparison of different lattice definitions of the topological charge
Cichy Krzysztof, Dromard Arthur, Garcia-Ramos Elena, Ottnad Konstantin, Urbach Carsten, Wagner Marc, Wenger Urs, Zimmermann Falk, Cichy Krzysztof, Dromard Arthur, Garcia-Ramos Elena, Ottnad Konstantin, Urbach Carsten, Wagner Marc, Wenger Urs, Zimmermann Falk (2015), Comparison of different lattice definitions of the topological charge, in PoS, LATTICE2014, 075-075.
Influence of topology on the scale setting
Bergner Georg, Giudice Pietro, Montvay Istvan, Münster Gernot, Piemonte Stefano, Bergner Georg, Giudice Pietro, Montvay Istvan, Münster Gernot, Piemonte Stefano (2015), Influence of topology on the scale setting, in Eur. Phys. J. Plus, 130(11), 229-229.
Infrared regime of SU(2) with one adjoint Dirac flavor
Athenodorou Andreas, Bennett Ed, Bergner Georg, Lucini Biagio, Athenodorou Andreas, Bennett Ed, Bergner Georg, Lucini Biagio (2015), Infrared regime of SU(2) with one adjoint Dirac flavor, in Phys. Rev., D91(11), 114508-114508.
Nonperturbative aspects of supersymmetric quantum field theories in low dimensions
Wenger Urs, Wenger Urs (2015), Nonperturbative aspects of supersymmetric quantum field theories in low dimensions, N/A, N/A.
Nonperturbative results for two-index conformal windows
Bergner Georg, Ryttov Thomas A., Sannino Francesco, Bergner Georg, Ryttov Thomas A., Sannino Francesco (2015), Nonperturbative results for two-index conformal windows, in JHEP, 12, 054-054.
Nucleon and pion structure with lattice QCD simulations at physical value of the pion mass
Abdel-Rehim A., others, Abdel-Rehim A., others (2015), Nucleon and pion structure with lattice QCD simulations at physical value of the pion mass, in Phys. Rev., D92(11), 114513-114513.
Numerical corrections to the strong coupling effective Polyakov-line action for finite T Yang-Mills theory
Bergner Georg, Langelage Jens, Philipsen Owe, Bergner Georg, Langelage Jens, Philipsen Owe (2015), Numerical corrections to the strong coupling effective Polyakov-line action for finite T Yang-Mills theory, in JHEP, 11, 010-010.
Progress in Simulations with Twisted Mass Fermions at the Physical Point
Abdel-Rehim A., others, Wenger U., Abdel-Rehim A., others, Wenger U. (2015), Progress in Simulations with Twisted Mass Fermions at the Physical Point, in PoS, LATTICE2014, 119-119.
Supermultiplets of the N=1 supersymmetric Yang-Mills theory in the continuum limit
Bergner Georg, Giudice Pietro, Montvay Istvan, Münster Gernot, Piemonte Stefano, Bergner Georg, Giudice Pietro, Montvay Istvan, Münster Gernot, Piemonte Stefano (2015), Supermultiplets of the N=1 supersymmetric Yang-Mills theory in the continuum limit, in PoS, LATTICE2015, 240-240.
Supersymmetric quantum mechanics on the lattice: I. Loop formulation
Baumgartner David, Wenger Urs, Baumgartner David, Wenger Urs (2015), Supersymmetric quantum mechanics on the lattice: I. Loop formulation, in Nucl. Phys., B894, 223-253.
Supersymmetric quantum mechanics on the lattice: II. Exact results
Baumgartner David, Wenger Urs, Baumgartner David, Wenger Urs (2015), Supersymmetric quantum mechanics on the lattice: II. Exact results, in Nucl. Phys., B897, 39-76.
Supersymmetric quantum mechanics on the lattice: III. Simulations and algorithms
Baumgartner David, Wenger Urs, Baumgartner David, Wenger Urs (2015), Supersymmetric quantum mechanics on the lattice: III. Simulations and algorithms, in Nucl. Phys., B899, 375-394.
The low-lying spectrum of $\mathcal N=1$ supersymmetric Yang-Mills theory
Giudice Pietro, Bergner Georg, Montvay Istvan, Münster Gernot, Piemonte Stefano, Giudice Pietro, Bergner Georg, Montvay Istvan, Münster Gernot, Piemonte Stefano (2015), The low-lying spectrum of $\mathcal N=1$ supersymmetric Yang-Mills theory, in PoS, EPS-HEP2015, 372-372.
Compactified $ \mathcalN=1 $ supersymmetric Yang-Mills theory on the lattice: continuity and the disappearance of the deconfinement transition
Bergner G., Piemonte S., Bergner G., Piemonte S. (2014), Compactified $ \mathcalN=1 $ supersymmetric Yang-Mills theory on the lattice: continuity and the disappearance of the deconfinement transition, in JHEP, 12, 133-133.
First studies of the phase diagram of N=1 supersymmetric Yang-Mills theory
Bergner G., Giudice P., Münster G., Piemonte S., Sandbrink D., Bergner G., Giudice P., Münster G., Piemonte S., Sandbrink D. (2014), First studies of the phase diagram of N=1 supersymmetric Yang-Mills theory, in PoS, LATTICE2014, 262-262.
Latest lattice results of N=1 supersymmetric Yang-Mills theory with some topological insights
Bergner Georg, Giudice Pietro, Montvay Istvan, Münster Gernot, Özugurel Umut D., Piemonte Stefano, Sandbrink Dirk, Bergner Georg, Giudice Pietro, Montvay Istvan, Münster Gernot, Özugurel Umut D., Piemonte Stefano, Sandbrink Dirk (2014), Latest lattice results of N=1 supersymmetric Yang-Mills theory with some topological insights, in PoS, LATTICE2014, 273-273.
Loop formulation of supersymmetric Yang-Mills quantum mechanics
Steinhauer Kyle, Wenger Urs, Steinhauer Kyle, Wenger Urs (2014), Loop formulation of supersymmetric Yang-Mills quantum mechanics, in JHEP, 12, 044-044.
Spontaneous supersymmetry breaking in the 2D $\mathcal N=$1 Wess-Zumino model
Steinhauer Kyle, Wenger Urs, Steinhauer Kyle, Wenger Urs (2014), Spontaneous supersymmetry breaking in the 2D $\mathcal N=$1 Wess-Zumino model, in Phys. Rev. Lett., 113(23), 231601-231601.
Canonical simulations of supersymmetric SU(N) Yang-Mills quantum mechanics
Bergner Georg, Liu Hang, Wenger Urs, Bergner Georg, Liu Hang, Wenger Urs, Canonical simulations of supersymmetric SU(N) Yang-Mills quantum mechanics, in PoS.
Large mass hierarchies from strongly-coupled dynamics
Athenodorou Andreas, Bennett Ed, Bergner Georg, Elander Daniel, Lin C. -J. David, Lucini Biagio, Piai Maurizio, Athenodorou Andreas, Bennett Ed, Bergner Georg, Elander Daniel, Lin C. -J. David, Lucini Biagio, Piai Maurizio, Large mass hierarchies from strongly-coupled dynamics, in JHEP.
Lattice simulations of technicolour theories with adjoint fermions and supersymmetric Yang-Mills theory
Bergner G., Giudice P., Münster G., Piemonte S., Montvay I., Bergner G., Giudice P., Münster G., Piemonte S., Montvay I., Lattice simulations of technicolour theories with adjoint fermions and supersymmetric Yang-Mills theory, in PoS.
Recent results from SU(2) with one adjoint Dirac fermion
Athenodorou Andreas, Bennett Ed, Bergner Georg, Lucini Biagio, Athenodorou Andreas, Bennett Ed, Bergner Georg, Lucini Biagio, Recent results from SU(2) with one adjoint Dirac fermion, in WSPC Proceedings.
Simulating QCD at the Physical Point with $N_f=2$ Wilson Twisted Mass Fermions at Maximal Twist
Abdel-Rehim A., others, Abdel-Rehim A., others, Simulating QCD at the Physical Point with $N_f=2$ Wilson Twisted Mass Fermions at Maximal Twist, in Phys.Rev. D.
Supersymmetry on the lattice
Bergner Georg, Catterall Simon, Bergner Georg, Catterall Simon, Supersymmetry on the lattice, in Intl.J.Mod.Phys. A.
Witten Index and Phase Diagram of Compactified N=1 Supersymmetric Yang-Mills Theory on the Lattice
Bergner G., Münster G., Piemonte S., Giudice P., Bergner G., Münster G., Piemonte S., Giudice P., Witten Index and Phase Diagram of Compactified N=1 Supersymmetric Yang-Mills Theory on the Lattice, in PoS.

Collaboration

Group / person Country
Types of collaboration
Flavour Lattice Averaging Group (FLAG) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
George Washington University, Washington United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
European Twisted Mass Collaboration (ETMC) Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
University of Münster Individual talk Nicht-störungstheoretische Perspektive auf die neue Physik jenseits des Standardmodells der Teilchenphysik 05.05.2016 Münster, Germany Bergner Georg;
EPFL Individual talk Supersymmetric Yang-Mills theory and adjoint QCD: Strong interactions beyond the standard model on the lattice 25.04.2016 Lausanne, Switzerland Bergner Georg;
University of Münster Individual talk Supersymmetric Yang-Mills theory on the lattice, the spectrum, compactifications, and reductions 18.01.2016 Münster, Germany Bergner Georg;
Inauguration Retreat of Research Training Group GRK 2149 at the University of Münster Talk given at a conference The adjoint version of QCD and the extension of the Standard Model of particle physics 24.11.2015 Münster, Germany Bergner Georg;
University of Southern Denmark Individual talk The conformal window for adjoint QCD -- Lattice simulations of supersymmetric Yang-Mills and technicolour theories 31.08.2015 Odense, Denmark Bergner Georg;
The 33rd International Symposium on Lattice Field Theory (LATTICE 2015) Talk given at a conference Canonical simulations of supersymmetric SU(N) Yang-Mills quantum mechanics (Wenger), Lattice simulations of technicolour theories with adjoint fermions and supersymmetric Yang-Mills theory (Bergner) 14.07.2015 Kobe, Japan Wenger Urs Rudolf; Bergner Georg;
Lattice Gauge Theory Simulations Beyond the Standard Model of Particle Physics Talk given at a conference Results from lattice simulations adjoint QCD and supersymmetric Yang-Mills theory 22.06.2015 Tel Aviv, Israel Bergner Georg;
Physics Colloquium, Department of Physics, Jagellonian University of Krakow Individual talk Challenges and prospects of lattice QCD 14.05.2015 Krakow, Poland Wenger Urs Rudolf;
Theory Seminar, Institute for Theoretical Physics, Jagellonian University of Krakow Individual talk Spontaneous supersymmetry breaking on the lattice 11.05.2015 Krakow, Poland Wenger Urs Rudolf;
University of Münster Individual talk Adjoint QCD and supersymmetric Yang-Mills theory on the lattice 27.04.2015 Münster, Germany Bergner Georg;
Habilitationsvortrag Individual talk Wie viel wiegt ein Proton? 12.03.2015 Bern, Switzerland Wenger Urs Rudolf;
University of Jena Individual talk Aspects of supersymmetric Yang-Mills and related theories: What can we learn from non-perturbative investigations? 04.11.2014 Jena, Germany Bergner Georg;


Self-organised

Title Date Place
Flavour Lattice Averaging Group (FLAG) workshop 07.04.2015 Bern, Switzerland

Communication with the public

Communication Title Media Place Year
Talks/events/exhibitions Wie viel wiegt ein Proton? German-speaking Switzerland 2015

Associated projects

Number Title Start Funding scheme
139196 Non-perturbative aspects of chiral symmetry and confinement in QCD and related theories 01.03.2012 SNSF Professorships

Abstract

In particle physics non-perturbative phenomena are ubiquituos and play important or even crucial roles. Quantum Chromodynamics (QCD) at low energies for example exhibits colour confinement and spontaneous breaking of chiral symmetry. The former is responsible for the fact that only composite colour-neutral particles, so-called hadrons, can be observed in nature, but not the quarks and gluons themselves, while the latter leads to the particular spectrum of the lightest hadrons observed in nature. The qualitative and quantitative understanding of such non-perturbative aspects of quantum field theories is of utmost importance for the justification of the underlying fundamental theories. In particular this also applies to QCD and its justification as the theory of the strong interactions and for the justification of the Standard Model (SM) in general.In this spirit the present proposal embraces two directions of research, both in the context of non-perturbative calculations in strongly interacting quantum field theories:(a) The first direction concerns the quantitative determination of low-energy properties of QCD via computer simulations from first principles. Precise ab-initio calculations at the physical point will enable a further reduction and control of the systematic errors present in such computations and will provide a further confirmation of the theoretical framework. The main challenges for non-perturbative QCD calculations lie e.g.~in the accurate and reliable determination of hadronic matrix elements and form factors which in many cases constitute the main source of theoretical uncertainties in the direct confrontation of the theory with experiment. Furthermore, such results will be used as valuable input into non-perturbative effects in SM phenomenology, and beyond, via the reduction of theoretical uncertainties in the hadronic sector. This will provide stringent tests of the SM and constitute an invaluable contribution towards the potential discovery of new Beyond the Standard Model (BSM) physics at the Large Hadron Collider (LHC).(b) The second direction concerns the non-perturbative study of strongly interacting supersymmetric (SUSY) quantum field theories in low dimensions on the lattice. While it is interesting per se to study various discretisation schemes for SUSY field theories regularised on the lattice, e.g.~using twisted SUSY or orbifolding techniques, our recent developments in simulating SUSY field theories in low dimensions efficiently and without critical slowing down brings the non-perturbative study of these theories to a new, unprecedented level of accuracy. Such quantitative studies are for example relevant for establishing spontaneous supersymmetry breaking phase transitions, or for the understanding of certain aspects of the gauge/gravity duality, e.g.~the relation between the thermodynamics of super Yang-Mills theory and the corresponding black hole string solutions in higher dimensions.
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