Floquet Time Crystals.
This work defines what it means for time translation symmetry to be spontaneously broken in a quantum system and shows that this occurs in a large class of many-body localized driven systems with discrete time-translation symmetry.
Pre-thermal phases of matter protected by time-translation symmetry
In a periodically driven (Floquet) system, there is the possibility for new phases of matter, not present in stationary systems, protected by discrete time-translation symmetry. This includes…
Symmetry-protected phases for measurement-based quantum computation.
- D. Else, I. Schwarz, S. Bartlett, A. Doherty
- PhysicsPhysical Review Letters
- 23 January 2012
A class of symmetry-protected topological orders in one-dimensional systems, any one of which ensures the perfect operation of the identity gate, can be a robust property of an entire phase in a quantum spin lattice, when protected by an appropriate symmetry.
Gauging spatial symmetries and the classification of topological crystalline phases
- Ryan Thorngren, D. Else
- Mathematics
- 2 December 2016
We put the theory of interacting topological crystalline phases on a systematic footing. These are topological phases protected by space-group symmetries. Our central tool is an elucidation of what…
Discrete Time Crystals
Experimental advances have allowed for the exploration of nearly isolated quantum many-body systems whose coupling to an external bath is very weak. A particularly interesting class of such systems…
Classification of topological phases in periodically driven interacting systems
We consider topological phases in periodically driven (Floquet) systems exhibiting many-body localization, protected by a symmetry $G$. We argue for a general correspondence between such phases and…
Non-Fermi Liquids as Ersatz Fermi Liquids: General Constraints on Compressible Metals
- D. Else, Ryan Thorngren, T. Senthil
- Physics
- 15 July 2020
A system with charge conservation and lattice translation symmetry has a well-defined filling $\nu$, which is a real number representing the average charge per unit cell. We show that if $\nu$ is…
Improved Lieb-Robinson bound for many-body Hamiltonians with power-law interactions
- D. Else, Francisco Machado, C. Nayak, N. Yao
- Computer SciencePhysical Review A
- 18 September 2018
A new family of Lieb-Robinson bounds for lattice spin systems with long-range interactions is proved, which allow us to prove that, at any fixed time, the spatial decay of quantum information follows arbitrarily closely to $1/r^{\alpha}$.
Crystalline topological phases as defect networks
- D. Else, Ryan Thorngren
- Materials SciencePhysical review B
- 24 October 2018
A crystalline topological phase is a topological phase with spatial symmetries. In this work, we give a very general physical picture of such phases: a topological phase with spatial symmetry $G$…
Cheshire charge in (3+1)-dimensional topological phases
We show that (3+1)-dimensional topological phases of matter generically support loop excitations with topological degeneracy. The loops carry "Cheshire charge": topological charge that is not the…
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