Name: Effective Field Theory Pollica
Start: 2022-06-20T09:00:00+02:00
End: 2022-07-01T19:00:00+02:00
Location: No location set

Effective Field Theory Pollica

from Monday, 20 June 2022 (09:00) to Friday, 1 July 2022 (19:00)

Monday, 20 June 2022

09:30 Welcome to week 1
Welcome to week 1
09:30 - 10:00
10:00 Chiral Magnetic Effect and Inverse Cascade in relativistic and non-relativistic systems - Alexey Boyarsky (Leiden U.)
Chiral Magnetic Effect and Inverse Cascade in relativistic and non-relativistic systems
- Alexey Boyarsky (Leiden U.)
10:00 - 11:00
We discuss how the instability towards the grows of helical magnetic fields appear in relativistic and in non-relativistic systems. We discuss many applications in physics and astrophysics and their importance for fundamental physics questions.
11:00 Coffe break
Coffe break
11:00 - 11:30

13:00 Lunch
Lunch
13:00 - 14:30
14:30 Chiral anomaly in Euler fluid - Alexander Abanov (Stony Brook)
Chiral anomaly in Euler fluid
- Alexander Abanov (Stony Brook)
14:30 - 15:30
We show that the chiral anomaly of quantum field theories with Dirac fermions subject to an axial background field is an inherent property of kinematics of a perfect classical fluid. We construct a variational principle generating classical equations of motion in the presence of background gauge fields. A prominent effect of the chiral anomaly is the transport electric current at equilibrium.
15:30 Coffe break
Coffe break
15:30 - 16:00
Tuesday, 21 June 2022
10:00 A new form of ergodicity breaking from quantum many-body scars - Maksym Serbyn (IST Austria)
A new form of ergodicity breaking from quantum many-body scars
- Maksym Serbyn (IST Austria)
10:00 - 11:00
In my introductory lectures I will review a new mechanism of the weak ergodicity breaking relevant for the experimentally realized Rydberg-atom quantum simulator [1]. This mechanism arises from the presence of special eigenstates in the many-body spectrum that are reminiscent of quantum scars in chaotic non-interacting systems [2]. In the single-particle case, quantum scars correspond to wave functions concentrated in the vicinity of unstable periodic classical trajectories. I will demonstrate that many-body scars appear in the Fibonacci chain, a model with a constrained local Hilbert space which can be realized by a Rydberg chain. The quantum scarred eigenstates are embedded throughout the otherwise thermalizing many-body spectrum but lead to direct experimental signatures, as I show for periodic recurrences that reproduce those observed in the experiment [1]. If time permits, I will also discuss the relation between scars and TDVP, and consider the interplay between quantum scars and quantum many-body control problems [3]. [1] Bernien, H. et al., Nature 551, 579–584 (2017), arXiv:1707.04344 [2] C. J. Turner, A. A. Michailidis, D. A. Abanin, M. Serbyn, Z. Papić, Nature Physics (May 2018), arXiv:1711.03528 and Phys. Rev. B 98, 155134 (2018) arXiv:1806.10933 [3] M. Ljubotina, B.Roos, D. Abanin, M. Serbyn, arXiv:2204.02899
11:00 Coffee break
Coffee break
11:00 - 11:30

13:00 Lunch
Lunch
13:00 - 14:30
14:30 QFTs emerging from many-body quantum physics - Jörg Schmiedmayer (TU-Wien)
QFTs emerging from many-body quantum physics
- Jörg Schmiedmayer (TU-Wien)
14:30 - 15:30
Quantum Field theories are a natural way to describe quantum many body systems. Irrelevant details of the microscopic physics are ignored and new relevant degrees of freedom, described by the QFT, emerge at a larger scale. I will illustrate this in the example of the emergence of the Sine-Gordon quantum field theory from the microscopic description of two tunnel coupled super fluids [1] and in the emergence of Pauli blocking in a weakly interacting Bose gas [2]. Special emphasis will be put on how to verify such emergent quantum simulators and how to characterize them. Thereby I will present two tools: High order correlation functions and their factorization [1], the evaluation of the quantum effective action and the momentum dependence of propagators and vertices (running couplings, renormalization of mass etc ..) of the emerging quantum field theory [3] and quantum field tomography that points to a new way to read out quantum simulators [4]. Together they establish general methods to analyse quantum systems through experiments and thus represents a crucial ingredient towards the implementation and verification of quantum simulators. As an example, I will report on the progress towards measuring area laws of mutual information and entanglement entropy in a QFT, and the study of information fronts in curved space time. Work performed in collaboration with the groups of Th. Gasenzer und J. Berges (Heidelberg), Jens Eisert (FU Berlin) and E. Demler (Harvard). Supported by the DFG-FWF: SFB ISOQUANT: and the EU: ERC-AdG QuantumRelax [1] T. Schweigler et al., Nature 545, 323 (2017), arXiv:1505.03126; [3] F. Cataldine et al. arXiv:2111.13647; [3] T. Zache et al. Phys. Rev. X 10, 011020 (2020); [4] M. Gluza et al., Communication Physics 3, 12 (2020).
15:30 Coffee break
Coffee break
15:30 - 16:00
Wednesday, 22 June 2022
10:00 Applied Fractons - Andrey Gromov (Brown)
Applied Fractons
- Andrey Gromov (Brown)
10:00 - 11:00
Fractons are a class of quasiparticles that cannot freely propagate through space. They were first introduced in a model of quantum (almost) self-correcting memory. Later it became clear that fractons, as well as, adjacent ideas such as tensor gauge theories and multipole or subsystem conservation laws provide a language to describe some known and some new phenomena. In this talk I will explain what fractons are, what kind of systems are known to support them and what kind of problems they will help to elucidate in the future.
11:00 Coffee break
Coffee break
11:00 - 11:30

13:00 Lunch
Lunch
13:00 - 14:30
14:30 Renormalization and thermodynamics of quantum membranes - Achille Mauri (Radboud U.)
Renormalization and thermodynamics of quantum membranes
- Achille Mauri (Radboud U.)
14:30 - 14:50
Thermally-fluctuating membranes have been the subject of extensive investigations, from biological systems to graphene and other atomically-thin 2D materials. This presentation introduces a field theoretical analysis of the effects of quantum and thermal fluctuations on the statistical mechanics of free-standing solid membranes. For zero temperature the interplay between phonon-phonon interactions and quantum fluctuations drives logarithmic renormalizations of elastic parameters. For small but nonzero temperatures, we use arguments of finite-size field theory to derive relations between the zero-point renormalizations and the low-temperature behavior of thermodynamic quantities such as the thermal expansion coefficient and the entropy. The analysis allows to revisit results obtained by different methods in earlier investigations.
14:50 Newton as Effective Field Theorist - Patrick Shields (Notre Dame)
Newton as Effective Field Theorist
- Patrick Shields (Notre Dame)
14:50 - 15:10
Abstract: In this talk, I will briefly discuss how Corollaries V and VI to the laws of motion in Newton's Principia can be thought of as defining EFTs from which we can recover Newton's laws using the coset construction. This is, in effect, reverse-engineering Newton's laws from the symmetry-breaking principles that result from them. I will conclude with some lessons from this about scientific understanding and how to think about what a physical theory is.
15:10 Looking into the early Universe with a solid-state device - Yevheniia Cheipesh (Leiden U.)
Looking into the early Universe with a solid-state device
- Yevheniia Cheipesh (Leiden U.)
15:10 - 15:30
Detecting relic neutrinos is a longstanding goal in fundamental physics. It is one of the predictions of the Standard Model that has not been yet confirmed. Additionally, it carries a photographic image of the early Universe, albeit from a much older epoch of neutrino decoupling. The conventional approach to this problem is to search for the peak in the spectrum of electrons emitted in a beta-decay. Experimentally, this goal is extremely challenging as the required energy resolution is defined by the tiny neutrino masses (~10 meV). While it seems possible to achieve a required energy resolution of the measuring apparatus, the intrinsic physics of the beta-emitting source imposes additional limitations.   The current consensus is that sufficient statistics together with the clean spectrum could only be achieved if beta decayers are attached to a solid state substrate. If one wants to keep the energy resolution as high as the mass of the neutrino, one needs to account for the presence of the solid state environment. This opens a whole new field of research in surface physics, both experimental and theoretical. I will outline the main directions and questions to be addressed and their implications for the design of the full scale relic neutrino experiment.
15:30 Coffee break
Coffee break
15:30 - 16:00
16:00 Genetic optimization of quantum annealing - Annarita Scocco (Scuola Superiore Meridionale)
Genetic optimization of quantum annealing
- Annarita Scocco (Scuola Superiore Meridionale)
16:00 - 16:20
Adiabatic quantum computation and quantum annealing exploit slow quantum evolutions to solve hard problems in different areas. Long-time dynamics are often infeasible and leave the system more prone to noise. Therefore we present a numerical approach based on genetic algorithms to speed up quantum annealing, optimizing the annealing schedules starting from the polynomial ansatz and exploiting shortcuts to adiabaticity. With this genetically optimized annealing schedules and/or optimal driving operators, we are able to perform quantum annealing in relatively short timescales and with higher fidelity compared to traditional approaches.
16:20 Electronic spectra of the pseudogap metal in the ancilla theory of the single band Hubbard model - Alexander Nikolaenko (Harvard)
Electronic spectra of the pseudogap metal in the ancilla theory of the single band Hubbard model
- Alexander Nikolaenko (Harvard)
16:20 - 16:40
The diverse phenomena associated with high-temperature superconductivity in the cuprates present a long-standing theoretical challenge. Various emerging phases have been thoroughly studied experimentally, including angle-resolved photoemission (ARPES), scanning tunnelling microscopy (STM), transport and thermodynamic measurements, but a complete theoretical understanding is still lacking. Many theoretical models have been proposed to describe the pseudogap regime of the cuprate superconductors. Some of them assume that the pseudogap is a precursor to some ordered phase, such as a spin density wave (SDW), or a charge density wave (CDW), or a pair density wave (PDW). A different class of models assume that the pseudogap is a distinct phase of matter characterized by spin liquid physics, which likely undergoes a confinement crossover to a more conventional broken symmetry phase at low temperatures. Here, we will investigate a model in the latter class, which describes the pseudogap metal as a fractionalized Fermi liquid (FL*): a state which has electronic quasiparticles around a Luttinger-rule violating small Fermi surface along with neutral spinon excitations. We will show how using a recently introduced 'ancilla' theory of FL* phases in a single band model yields simple models which can be successfully compared to a wide range of ARPES experiments in Bi2212 and Bi2201 in both the nodal and anti-nodal regions of the Brillouin zone.
16:40 Apparently Superluminal Superfluids - Ioanna Kourkoulou (Columbia)
Apparently Superluminal Superfluids
- Ioanna Kourkoulou (Columbia)
16:40 - 17:00
The superfluid 4-velocity becomes space-like when approaching a vortex core, while still keeping enough distance to stay within the regime of validity of the EFT. The fluctuations around this background are stable. This is in contrast to the case of normal fluids, which develop instabilities around a spacelike background current.
Thursday, 23 June 2022
10:00 Identifying non-abelian channels in exotic quantum Hall states - Mitali Banjeree (EPFL)
Identifying non-abelian channels in exotic quantum Hall states
- Mitali Banjeree (EPFL)
10:00 - 11:00
Quantum Hall states – the progenitors of the growing family of topological insulators – are also a source of exotic quantum states. These states can be abelian (e.g., integers & fractions) or non-abelian (e.g., special fractions)., and thus may host electrons, fractionally charged quasiparticles, and neutral bosonic or Majorana (in general, para-fermionic) quasiparticles. Since the bulk is insulating (with the quasiparticles localized), counter-propagating gapless edge modes mirror the bulk’s topological order (due to ‘bulk-edge’ correspondence). The most theoretically studied non-abelian state has a filling 𝜈=5/2. The state supports charge- neutral quasiparticles accompanied by e/4 charges. This filling, however, permits different topological orders, which can be abelian or non-abelian. While numerical calculations favor the non-abelian Anti- Pfaffian (A-Pf) order, our recent thermal conductance measurements found the unexpected order, Particle-Hole Pfaffian (PH-Pf). Employing a novel interface method, where the bulk of the 𝜈=5/2 filling was interfaced with a bulk of integer filling 𝜈=2 or 𝜈=3, an isolated interface channel of 𝜈=1/2 emerged. Studying the latter via measuring heat flow, we re-verified the PH-Pf order of the 𝜈=5/2 state (and its non-abelian nature). Identifying the correct topological order is crucial in testing the numerical predictions. While such experiments are more complicated than the ubiquitous conductance measurements, their ‘power’ is already evident. Moreover, isolating the fractional channel can be most helpful in complex interference (braiding) experiments. Banerjee et al, Nature. 545, 7652, 75-79 (2017). Banerjee et al, Nature. 559, 7713, 205-210 (2018). Dutta et al., Science. 375, 6577, 193-197 (2021). Dutta et al., arXiv: 2109.11205, (accepted in Science).
11:00 Coffee break
Coffee break
11:00 - 11:30

13:00 Lunch
Lunch
13:00 - 14:30
14:30 Thermodynamics and conformal operators of the Sachdev-Ye-Kitaev model - Grigory Tarnopolskiy (Carnegie Mellon)
Thermodynamics and conformal operators of the Sachdev-Ye-Kitaev model
- Grigory Tarnopolskiy (Carnegie Mellon)
14:30 - 15:30
Quantum mechanical models with random interactions have an infinite number of bilinear operators, the scaling dimensions of which can be computed explicitly in the large N limit. The lowest dimension operators play an important role in thermodynamical properties of these models and define the behavior of various correlation functions in the infrared limit. In this talk I’ll discuss effects of these operators on the SYK model free-energy and its numerical observation.
15:30 Coffee break
Coffee break
15:30 - 16:00
Friday, 24 June 2022
10:00 Plaquette-dimer liquid beyond renormalization - Yizhi You (Oxford)
Plaquette-dimer liquid beyond renormalization
- Yizhi You (Oxford)
10:00 - 11:00
We consider close-packed tiling models of geometric objects -- a mixture of hardcore dimers and plaquettes -- as a generalisation of the familiar dimer models. Specifically, on an anisotropic cubic lattice, we demand that each site be covered by either a dimer on a z-link or a plaquettein the x-y plane. The space of such fully packed tilings has an extensive degeneracy. This maps onto a fracton-type `higher-rank electrostatics', which can exhibit a plaquette-dimer liquid and an ordered phase. We analyse this theory in detail, using height representations and T-duality to demonstrate that the concomitant phase transition occurs due to the proliferation of dipoles formed by defect pairs. The resultant critical theory can be considered as a fracton version of the Kosterlitz-Thouless transition. A significant new element is its UV-IR mixing, where the low energy behavior of the liquid phase and the transition out of it is dominated by local (short-wavelength) fluctuations, rendering the critical phenomenon beyond the renormalization group paradigm.
11:00 Coffee break
Coffee break
11:00 - 11:30

13:00 Lunch
Lunch
13:00 - 14:30

14:30 Leaded by Alexander Abanov & Maksym Serbyn
Leaded by Alexander Abanov & Maksym Serbyn
14:30 - 15:30

15:30 Coffee break
Coffee break
15:30 - 16:00
Saturday, 25 June 2022
Sunday, 26 June 2022