Theory Canada 14

Session

Talks

31 May 2019, 09:00

Hennings 318 (UBC)

Conveners

Talks: Morning 1

• Nirmal Raj (TRIUMF)

Talks: Morning 2

• Matteo Vorabbi (TRIUMF)

Talks: Afternoon 1

• Joanna Karczmarek

Talks: Afternoon 2

• David McKeen (TRIUMF)

Talks: Morning 3

• Ragnar Stroberg (University of Washington)

Talks: Morning 4

• Olivia Di Matteo (TRIUMF)

Talks: Afternoon 3

• Ariel Edery (Bishop's University)

Talks: Afternoon 4

• David Morrissey (TRIUMF)

31. The Majorana-Hubbard Model

Prof. Ian Affleck (University of British Columbia)

31/05/2019, 09:00

A superconductor in a magnetic field in proximity with a topological insulator is predicted to have a Majorana mode (corresponding to a Hermitian fermion operator) at the centre of each vortex core. The low energy Hamiltonian for these fermion operators has both hopping terms and interaction terms. By tuning the chemical potential in the topological insulator it is possible to set the hopping...

27. Quantum Material Simulation with D-Wave Processors

Dr Mohammad Amin (D-Wave Systems Inc.)

31/05/2019, 09:30

One of the most natural and also probably most important applications of quantum computation is simulation of other quantum systems. Qubits are particularly suitable for simulating spin-1/2 particles in magnetic materials. In this presentation, after a brief introduction to D-Wave quantum processors, I provide examples in which D-Wave qubits were used for simulation of quantum magnetic systems...

25. Reduced Quantum Dynamics from Observables

Dr Jason Pollack (University of British Columbia)

31/05/2019, 10:00

When they can be defined, reduced density matrices provide a powerful tool for determining the entanglement structure, approximate dynamics, and potential classical behavior of a portion of a quantum system. It is straightforward to generate a reduced density matrix by tracing out a portion of the full density matrix of a (pure or mixed) quantum state of the full system, but many natural...

17. Quantum Chaos and Effective Field Theory

Dr Felix Haehl (UBC Vancouver)

31/05/2019, 10:15

I discuss the physics of quantum chaos in conformal field theories with a large number of degrees of freedom. We focus on two-dimensional theories, but also comment on the one-dimensional case (related to the SYK model) and higher-dimensional generalizations. A novel formulation using effective field theory methods at large central charge provides a useful perspective and computational...

22. The Status of the Nuclear Shell Model

Ragnar Stroberg (University of Washington)

31/05/2019, 11:00

For 70 years, the nuclear shell model has provided the conceptual and computational framework for most of low-energy nuclear structure. In particular, since the 1980s large-scale shell model calculations have achieved remarkable success in reproducing and (sometimes) predicting experimental data. However, these calculations are inevitably phenomenological in nature, with parameters fit to the...

8. Nuclear reactions important for astrophysics from ab initio theory

Dr Petr Navratil (TRIUMF)

31/05/2019, 11:30

In recent years, significant progress has been made in ab initio nuclear structure and dynamics calculations based on input from QCD employing Hamiltonians constructed within chiral effective field theory. One of the newly developed approaches is the No-Core Shell Model with Continuum (NCSMC) [1,2], capable of describing both bound and unbound states in light nuclei in a unified way. I will...

32. Forging the Universe's gold

Prof. Daniel Siegel (Perimeter Institute for Theoretical Physics & University of Guelph)

31/05/2019, 11:45

Gravitational-wave observatories are currently revolutionizing astrophysics and astronomy. Detections of neutron star mergers trigger follow-up campaigns of unprecedented scope by astronomers and particle (astro)physicists worldwide. In this talk, I will attempt to provide an overview of some exciting recent results at the interface of high-energy astrophysics, strong gravity, and nuclear...

5. Emergence of a Black Hole at the Centre of some Galaxies

Prof. Réjean Plamondon (Polytechnique Montréal)

31/05/2019, 12:15

Over the last CAP and Theory Canada conferences, we have proposed a conceptual framework to rationalize the use of an erfc potential in a modified Schwarzchild spacetime geometry [1]. Starting from the premise of an interdependence principle interpreted in a Bayesian setting, the linear case of a weak field static symmetric massive object was analyzed to point out how Einstein’s equation could...

28. An index for interacting topological phases

Prof. Sven Bachmann (University of British Columbia)

31/05/2019, 14:00

I will discuss an index associated to a local unitary and a projection in the setting of many-body interacting particles on a lattice. Its values are in general rational, being integer multiples of the inverse of the rank of the projection. In the appropriate setting, the index is the Hall conductance.

29. An Introduction to Knot Theory from String Theory

Prof. Keshav Dasgupta (McGill University)

31/05/2019, 14:30

In this talk I'll summarize some of the recent developments in both computing and understanding knot polynomials using certain brane constructions from string theory. The talk will be pedagogical and accessible to physicists with minimal knowledge of string theory.

20. Near-extremal Black Holes and Jackiw-Teitelboim Gravity

Dr Ashish Shukla (University of Victoria)

31/05/2019, 15:00

I will talk about the dynamics of near-extremal Reissner-Nordstrom black holes in four-dimensional asymptotically AdS space. Working in the spherically symmetric approximation, I will present results about the thermodynamics and the response of the system to a probe scalar field. I will present evidence that the dynamics in the low energy limit is very well captured by the two-dimensional...

16. From alpha clustering to homogeneous nucleonic matter

Alex Gezerlis (University of Guelph)

31/05/2019, 15:45

Over the last few decades the study of nuclei and neutron-rich matter from first principles has entered a new era. This has partly been driven by the development of novel interactions between two or three nucleons. In an attempt to produce a systematic expansion, several groups have produced Effective Field Theory (EFT) interactions, whether of finite range (chiral EFT) or zero range (pionless...

26. Two-major shell-model effective Hamiltonian from in-medium similarity renormalization group approach

Dr Takayuki Miyagi (TRIUMF)

31/05/2019, 16:15

In the past decade, many efforts have been made in the ab initio calculations. The capability of ab initio many-body calculations has reached to mass number 100 region. The calculation methods which are available for the medium-mass region such as coupled-cluster method, self-consistent Green's function method, and in-medium similarity renormalization group (IM-SRG) are typically limited the...

12. Investigation of the A=7 systems within the No-Core Shell Model with Continuum

Dr Matteo Vorabbi (TRIUMF)

31/05/2019, 16:30

One of the recently developed approaches capable of describing both bound and scattering states in light nuclei simultaneously is the No-Core Shell Model with Continuum (NCSMC). This technique represents a state-of-the-art *ab initio* approach and combines the No-Core Shell Model (NCSM) description of short-range correlations with the clustering and scattering properties of the Resonating...

30. Higher-Curvature Gravity, Black Holes, and Holography

Dr Robie Hennigar (Memorial University of Newfoundland)

01/06/2019, 09:00

Quantum gravitational effects are expected to produce higher-curvature modifications to general relativity, but the complete structure of these modifications is unknown. Nonetheless, the study of generic higher-curvature gravities has proven useful, providing valuable insights into the nature of black hole thermodynamics and helping to uncover universal properties for field theories via...

4. Gravitating magnetic monopole via the spontaneous symmetry breaking of pure R^2 gravity

Prof. Ariel Edery (Bishop's University)

01/06/2019, 09:30

The pure $R^2$ gravity is equivalent to Einstein gravity with cosmological constant and a massless scalar field and it further possesses the so-called restricted Weyl symmetry which is a symmetry larger than scale symmetry. To incorporate matter, we consider a restricted Weyl invariant action composed of pure $R^2$ gravity, SU(2) Yang-Mills fields and a non-minimally coupled massless Higgs...

1. A connection between linearized Gauss–Bonnet gravity and classical electrodynamics

Mr Mark Baker (Western University)

01/06/2019, 09:45

The oral presentation will consist primarily of a recently published article in International Journal of Modern Physics D entitled "A connection between linearized Gauss–Bonnet gravity and classical electrodynamics", authored by MR Baker and S Kuzmin. In this article, a connection between a well known gravitational model and classical electrodynamics is derived. Given the excitement among...

9. On Negative Mass

Prof. Manu Paranjape (Université de Montréal)

01/06/2019, 10:00

We review the notion of negative mass in general relativity. We show the existence of stable, thin wall bubbles in a de Sitter background. The outside metric is the exact negative mass Schwarzschild-de Sitter metric, while inside, it is a smooth non-singular metric, with a corresponding energy-momentum tensor that satisfies the dominant energy condition.

18. Thermodynamic Parameters of a Boulware-Deser Black Hole from Fluid-Gravity Correspondence

Mr Dylan Sutherland (University of Lethbridge)

01/06/2019, 10:15

As a solution to the equations of Lanczos-Lovelock Gravity (a natural extension of General Relativity for higher dimensions), the Boulware-Deser black hole presents as an interesting system. Indeed, given the universal success had to this point by prospective theories of quantum gravity in modelling the Schwartzchild black hole, the next challenge for such theories may be found in correctly...

21. High-frequency gravitational-wave astronomy

Dr Huan Yang (Uniersity of Guelph)

01/06/2019, 11:00

In this talk I will discuss some recent development towards detecting gravitational waves in the kilo Hertz band. On the detector side, we propose a new interferometer design that significantly improves detector sensitivity above 1 kHz. On the science front, we identify several key questions that can be answered by combining high-frequency gravitational-wave detection and electromagnetic...

7. New Gravitational Probes of Dark Matter

Dr Evan McDonough (Brown University)

01/06/2019, 11:30

Despite decades of searching, the strongest evidence for dark matter remains gravitational. It is thus worthwhile to consider the extent to which gravitational probes can discriminate between models of cold dark matter. With this in mind, in this talk I will discuss the early universe origins and late universe observables of "superfluid" dark matter. Despite having only gravitational couplings...

3. On the quantum origin of a small positive cosmological constant

Prof. Saurya Das (University of Lethbridge)

01/06/2019, 12:00

We show that Dark Matter consisting of ultralight bosons in a Bose-Einstein condensate induces, via its quantum potential, a small positive cosmological constant which matches the observed value. This explains its origin and why the densities of Dark Matter and Dark Energy are approximately equal. References: S.Das, R. K. Bhaduri, arXiv:1808.10505, arXiv:1812.07647

13. Custodial symmetry and the Higgs sector

Heather Logan (Carleton University)

01/06/2019, 14:00

Custodial symmetry is an accidental symmetry of the Standard Model Higgs sector that underlies the well-tested relationship between the W and Z boson masses and their gauge couplings. In extended Higgs sectors this symmetry can be violated, with potentially fatal experimental consequences. I'll describe the effects of this violation in the Georgi-Machacek model, which serves as a prototype...

23. Interference Effects in Higgs Decays

Prof. Daniel Stolarski (Carleton University)

01/06/2019, 14:30

I will describe how measurements of interference effects in Higgs decays at the LHC can lead to novel measurements of parameters that are difficult to constrain in other ways such as the sign of the ratio of the Higgs coupling to the W relative to the Z boson.

15. Sending quantum information through a quantum field

Petar Simidzija (University of Waterloo)

01/06/2019, 15:30

The theory of classical information transmission through quantum fields has been extensively studied in previous literature. On the other hand, while there have been successful experiments transmitting quantum information over hundreds of kilometres, our understanding of the fundamental mechanism by which quantum information is broadcast through a quantum field has been limited. In this talk...

6. Quantum tasks in holography

Mr Alex May (University of British Columbia)

01/06/2019, 16:00

We consider an operational restatement of the holographic principle, which we call the principle of asymptotic quantum tasks. Asymptotic quantum tasks are quantum information processing tasks with inputs given and outputs required on points at the boundary of a spacetime. The principle of asymptotic quantum tasks states that tasks which are possible using the bulk dynamics should coincide with...

14. Relativistic Generalized Uncertainty Principle and minimum length

Mr Vasil Todorinov (University of Lenthbridge)

01/06/2019, 16:15

Theories of Quantum Gravity predict a minimum measurable length and acorresponding modification of the Heisenberg Uncertainty Principle to theso-called Generalized Uncertainty Principle (GUP). However, this modification isnon-relativistic, making it unclear whether the minimum length is Lorentzinvariant. We formulate aRelativisticGeneralized Uncertainty Principle, resultingin aLorentz...

24. The SJ Vacuum in de Sitter Spacetime

Yasaman Yazdi (University of Alberta)

01/06/2019, 16:30

I present results from a study of the Sorkin-Johnston (SJ) vacuum in de Sitter spacetime for a free scalar field theory. We find evidence for a new vacuum state in de Sitter spacetime which is de Sitter invariant in 4d. Using a causal set discretisation of a slab of 2d and 4d de Sitter spacetime, we find the causal set SJ vacuum for a range of masses $m\ge 0$ of the free scalar field. ...