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How neutron star mergers can be used to study hadron-quark phase transitions

Elias Most Princeton University
November 28, 2019

PIRSA:19110147
Strong Gravity
PSI 2019/2020 - Condensed Matter (Wang) - Lecture 11

Chong Wang Perimeter Institute for Theoretical Physics
November 28, 2019

PIRSA:19110037
Condensed Matter
Stabilizer codes for prime power qudits

Daniel Gottesman University of Maryland, College Park
November 28, 2019

PIRSA:19110138
Quantum Information
Self-correction from symmetry

Sam Roberts PsiQuantum Corp.
November 28, 2019

PIRSA:19110137
Quantum Information
PSI 2019/2020 - Quantum Field Theory II (David) - Lecture 11

Francois David CEA Saclay
November 28, 2019

PIRSA:19110022
Quantum Fields and Strings
Towards local testability for quantum coding

Anthony Leverrier Inria Paris Centre
November 27, 2019

PIRSA:19110133
Quantum Information
A computationally universal phase of quantum matter

Robert Raussendorf Leibniz University Hannover
November 27, 2019

PIRSA:19110116
Quantum Information
Fine-grained quantum supremacy and stabilizer rank

Tomoyuki Morimae Kyoto University
November 27, 2019

PIRSA:19110131
Quantum Information
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 9
- Meng Guo University of Illinois Urbana-Champaign
- Theo Johnson-Freyd Dalhousie University
November 27, 2019

PIRSA:19110045
Other
Classical algorithms for quantum mean values

David Gosset Institute for Quantum Computing (IQC)
November 27, 2019

PIRSA:19110130
Quantum Information
PSI 2019/2020 - Quantum Field Theory II (David) - Lecture 10

Francois David CEA Saclay
November 27, 2019

PIRSA:19110020
Quantum Fields and Strings
Magic resource theories and classical simulation

Earl Campbell University of Sheffield
November 26, 2019

PIRSA:19110122
Quantum Information

How neutron star mergers can be used to study hadron-quark phase transitions

Elias Most Princeton University
November 28, 2019

PIRSA:19110147
Strong Gravity
With the detection of GW170817 we have observed the first multi messenger signal from two merging neutron stars. This signal carried a multitude of information about the underlying equation of state (EOS) of nuclear matter, which so far is not known for densities above nuclear saturation. In particular it is not known if exotic states or even a phase transition to quark matter can occur at densities so extreme that they can't be probed by any current experiment.

I will show how the information carried in the gravitational wave signal of GW170817 can be used to constrain the EOS at densities above saturation and what we can learn about the possible existence of phase transitions. I will
also comment on how we can improve on those limits with upcoming observations of the NICER mission.In the second part of the talk I will focus on what we can learn about exotic states of matter from neutron star mergers.I will comment briefly on the impact of high spins in mergers and the importance of accurate numerical modelling in the context of these studies.Finally I will show how neutron star mergers can be used to study quark phase transitions and the phase diagram of QCD.
PSI 2019/2020 - Condensed Matter (Wang) - Lecture 11

Chong Wang Perimeter Institute for Theoretical Physics
November 28, 2019

PIRSA:19110037
Condensed Matter
Stabilizer codes for prime power qudits

Daniel Gottesman University of Maryland, College Park
November 28, 2019

PIRSA:19110138
Quantum Information
There is a standard generalization of stabilizer codes to work with qudits which have prime dimension, and a slightly less standard generalization for qudits whose dimension is a prime power. However, for prime power dimensions, the usual generalization effectively treats the qudit as multiple prime-dimensional qudits instead of one larger object. There is a finite field GF(q) with size equal to any prime power, and it makes sense to label the qudit basis states with elements of the finite field, but the usual stabilizer codes do not make use of the structure of the finite field. I introduce the true GF(q) stabilizer codes, a subset of the usual prime power stabilizer codes which do make full use of the finite field structure. The true GF(q) stabilizer codes have nicer properties than the usual stabilizer codes over prime power qudits and work with a lifted Pauli group, which has some interesting mathematical aspects to it.
Self-correction from symmetry

Sam Roberts PsiQuantum Corp.
November 28, 2019

PIRSA:19110137
Quantum Information
A self-correcting quantum memory can store and protect quantum information for a time that increases without bound in the system size, without the need for active error correction. Unfortunately, the landscape of Hamiltonians based on stabilizer (subspace) codes is heavily constrained by numerous no-go results and it is not known if they can exist in three dimensions or less. In this talk, we will discuss the role of symmetry in self-correcting memories. Firstly, we will demonstrate that codes given by 2D symmetry-enriched topological (SET) phases that appear naturally on the boundary of 3D symmetry-protected topological (SPT) phases can be self-correcting -- provided that they are protected by an appropriate subsystem symmetry. Secondly, we discuss the feasibility of self-correction in Hamiltonians based on subsystem codes, guided by the concept of emergent symmetries. We present ongoing work on a new exactly solvable candidate model in this direction based on the 3D gauge color code. The model is a non-commuting, frustrated lattice model which we prove to have an energy barrier to all bulk errors. Finding boundary conditions that encode logical qubits and retain the bulk energy barrier remains an open question.
PSI 2019/2020 - Quantum Field Theory II (David) - Lecture 11

Francois David CEA Saclay
November 28, 2019

PIRSA:19110022
Quantum Fields and Strings
Towards local testability for quantum coding

Anthony Leverrier Inria Paris Centre
November 27, 2019

PIRSA:19110133
Quantum Information
We introduce the hemicubic codes, a family of quantum codes obtained by associating qubits with the p-faces of the n-cube (for n>p) and stabilizer constraints with faces of dimension (p±1). The quantum code obtained by identifying antipodal faces of the resulting complex encodes one logical qubit into N=2n−p−1(np) physical qubits and displays local testability with a soundness of Ω(log−2(N)) beating the current state-of-the-art of log−3(N) due to Hastings. We exploit this local testability to devise an efficient decoding algorithm that corrects arbitrary errors of size less than the minimum distance, up to polylog factors. We then extend this code family by considering the quotient of the n-cube by arbitrary linear classical codes of length n. We establish the parameters of these generalized hemicubic codes. Interestingly, if the soundness of the hemicubic code could be shown to be 1/log(N), similarly to the ordinary n-cube, then the generalized hemicubic codes could yield quantum locally testable codes of length not exceeding an exponential or even polynomial function of the code dimension. (joint work with Vivien Londe and Gilles Zémor)
A computationally universal phase of quantum matter

Robert Raussendorf Leibniz University Hannover
November 27, 2019

PIRSA:19110116
Quantum Information
We provide the first example of a symmetry protected quantum phase that has universal computational power. Throughout this phase, which lives in spatial dimension two, the ground state is a universal resource for measurement based quantum computation. Joint work with Cihan Okay, Dong-Sheng Wang, David T. Stephen, Hendrik Poulsen Nautrup; J-ref: Phys. Rev. Lett. 122, 090501
Fine-grained quantum supremacy and stabilizer rank

Tomoyuki Morimae Kyoto University
November 27, 2019

PIRSA:19110131
Quantum Information
It is known that several sub-universal quantum computing models cannot be classically simulated unless the polynomial-time hierarchy collapses. However, these results exclude only polynomial-time classical simulations. In this talk, based on fine-grained complexity conjectures, I show more ``fine-grained" quantum supremacy results that prohibit certain exponential-time classical simulations. I also show the stabilizer rank conjecture under fine-grained complexity conjectures.
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 9
- Meng Guo University of Illinois Urbana-Champaign
- Theo Johnson-Freyd Dalhousie University
November 27, 2019

PIRSA:19110045
Other
Classical algorithms for quantum mean values

David Gosset Institute for Quantum Computing (IQC)
November 27, 2019

PIRSA:19110130
Quantum Information
Consider the task of estimating the expectation value of an n-qubit tensor product observable in the output state of a shallow quantum circuit. This task is a cornerstone of variational quantum algorithms for optimization, machine learning, and the simulation of quantum many-body systems. In this talk I will describe three special cases of this problem which are "easy" for classical computers. This is joint work with Sergey Bravyi and Ramis Movassagh.
PSI 2019/2020 - Quantum Field Theory II (David) - Lecture 10

Francois David CEA Saclay
November 27, 2019

PIRSA:19110020
Quantum Fields and Strings
Magic resource theories and classical simulation

Earl Campbell University of Sheffield
November 26, 2019

PIRSA:19110122
Quantum Information
I will review the stabiliser rank and associated pure state magic monotone, the extent, [Bravyi et. al 2019]. Then I will discuss several new magic monotones that can be regarded as a generalisation of the extent monotone to mixed states [Campbell et. al., in preparation]. My talk will outline several nice theorems we can prove about these monotones relate to each other and how they are related to the runtime of new classical simulation algorithms.

Title	Date	Collection	Type	Info
How neutron star mergers can be used to study hadron-quark phase transitions	2019‑11‑28	Strong Gravity	Scientific Series	View details
PSI 2019/2020 - Condensed Matter (Wang) - Lecture 11	2019‑11‑28	PSI 2019/2020 - Condensed Matter (Wang)	Course	View details
Stabilizer codes for prime power qudits	2019‑11‑28	Symmetry, Phases of Matter, and Resources in Quantum Computing	Conference	View details
Self-correction from symmetry	2019‑11‑28	Symmetry, Phases of Matter, and Resources in Quantum Computing	Conference	View details
PSI 2019/2020 - Quantum Field Theory II (David) - Lecture 11	2019‑11‑28	PSI 2019/2020 - Quantum Field Theory II (David)	Course	View details
Towards local testability for quantum coding	2019‑11‑27	Symmetry, Phases of Matter, and Resources in Quantum Computing	Conference	View details
A computationally universal phase of quantum matter	2019‑11‑27	Colloquium	Scientific Series	View details
Fine-grained quantum supremacy and stabilizer rank	2019‑11‑27	Symmetry, Phases of Matter, and Resources in Quantum Computing	Conference	View details
The Cohomology of Groups (Johnson-Freyd/Guo) - Lecture 9	2019‑11‑27	The Cohomology of Groups (Johnson-Freyd/Guo)	Course	View details
Classical algorithms for quantum mean values	2019‑11‑27	Symmetry, Phases of Matter, and Resources in Quantum Computing	Conference	View details
PSI 2019/2020 - Quantum Field Theory II (David) - Lecture 10	2019‑11‑27	PSI 2019/2020 - Quantum Field Theory II (David)	Course	View details
Magic resource theories and classical simulation	2019‑11‑26	Symmetry, Phases of Matter, and Resources in Quantum Computing	Conference	View details

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