Format results
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Non-Gaussian fermionic ansatzes from many-body correlation measures
Yaroslav Herasymenko - Perimeter Institute for Theoretical Physics
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Fermi Surface Anomaly and Symmetric Mass Generation
Yi-Zhuang You - University of California, San Diego
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The Higher Berry Phase and Matrix Product States
Shuhei Ohyama - Kyoto University
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Quantum entropy thermalization
Yichen Huang - Massachusetts Institute of Technology (MIT)
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Discrete shift and quantized charge polarization: New invariants in crystalline topological states
Naren Manjunath - Perimeter Institute for Theoretical Physics
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Nonadiabatically Boosting the Quantum State of a Cavity
David Long - Boston University
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Topology of the Fermi sea: ordinary metals as topological materials
Pok Man Tam - University of Pennsylvania
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Average Symmetry-Protected Topological Phases: Construction and Detection
Jianhao Zhang - Pennsylvania State University
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Equivariant Higher Berry classes and chiral states
Nikita Sopenko - Institute for Advanced Study (IAS) - School of Natural Sciences (SNS)
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Non-Gaussian fermionic ansatzes from many-body correlation measures
Yaroslav Herasymenko - Perimeter Institute for Theoretical Physics
The notorious exponential complexity of quantum problems can be avoided for systems with limited correlations. For example, states of one-dimensional systems with bounded entanglement are approximable by matrix product states. We consider fermionic systems, where correlations can be defined as… -
Lieb-Schultz-Mattis, ’t Hooft and Luttinger: anomalies in lattice systems
Meng Cheng - Yale University
Macroscopic physics of a quantum many-body systems on a lattice is commonly captured by a continuum field theory. We will discuss the interplay between lattice effects and continuum theory from the perspective of symmetry and ’t Hooft anomalies. In the first part of the talk, using the example of a… -
Fermi Surface Anomaly and Symmetric Mass Generation
Yi-Zhuang You - University of California, San Diego
Fermi liquids are gapless quantum many-body states of fermions, which describes electrons in the normal state of most metals at low temperature. Despite its long history of study, there has been renewed interest in understanding the stability of Fermi liquid from the perspectives of emergent… -
A model of the cuprates: from the pseudogap metal to d-wave superconductivity and charge order
Subir Sachdev - Harvard University
Soon after the discovery of high temperature superconductivity in the cuprates, Anderson proposed a connection to quantum spin liquids. But observations since then have shown that the low temperature phase diagram is dominated by conventional states, with a competition between superconductivity and… -
The Higher Berry Phase and Matrix Product States
Shuhei Ohyama - Kyoto University
The Berry phase, discovered by M.V. Berry in 1984, has been applied to the construction of various invariants in topological phase of matters. The Berry phase measures the non-triviality of a uniquely gapped system as a family and takes its value in $H^2({parameter space};Z)$. In recent years, there… -
Quantum entropy thermalization
Yichen Huang - Massachusetts Institute of Technology (MIT)
In an isolated quantum many-body system undergoing unitary evolution, the entropy of a subsystem (smaller than half the system size) thermalizes if at long times, it is to leading order equal to the thermodynamic entropy of the subsystem at the same energy. We prove entropy thermalization for a… -
A lossy atom that does not decay: PT symmetry and coherent dynamics with complex energies
Yogesh Joglekar - Indiana University
Isolated quantum systems, investigated a century ago, exhibit coherent, unitary dynamics. When such a system is coupled to an environment, the resulting loss of coherence is modeled by completely positive, trace preserving (CPTP) quantum maps for the density matrix. A lossy atom, when it has not… -
Discrete shift and quantized charge polarization: New invariants in crystalline topological states
Naren Manjunath - Perimeter Institute for Theoretical Physics
In this talk I will describe a topological response theory that predicts the physical manifestation of a class of topological invariants in systems with crystalline symmetry. I focus on two such invariants, the 'discrete shift' and a quantized charge polarization. Guided by theory, I discuss how… -
Nonadiabatically Boosting the Quantum State of a Cavity
David Long - Boston University
Periodic driving is a ubiquitous tool for controlling experimental quantum systems. When the drive fields are of comparable, incommensurate frequencies, new theoretical tools are required to treat the resulting quasiperiodic time dependence. Similarly, new and surprising phenomena of topological… -
Topology of the Fermi sea: ordinary metals as topological materials
Pok Man Tam - University of Pennsylvania
It has long been known that the quantum ground state of a metal is characterized by an abstract manifold in the momentum space called the Fermi sea. Fermi sea can be distinguished topologically in much the same way that a ball can be distinguished from a donut by counting the number of holes. The… -
Average Symmetry-Protected Topological Phases: Construction and Detection
Jianhao Zhang - Pennsylvania State University
Symmetry-protected topological (SPT) phases are short-range entanglement (SRE) quantum states which cannot be adiabatically connected to trivial product states in the presence of symmetries. Recently, it is shown that symmetry-protected short-range entanglement can still prevail even if part of the… -
Equivariant Higher Berry classes and chiral states
Nikita Sopenko - Institute for Advanced Study (IAS) - School of Natural Sciences (SNS)
I will talk about the generalization of Berry classes for quantum lattice spin systems. It defines invariants of topologically ordered states or families thereof. In particular, its equivariant version for 2d gapped states gives the zero-temperature Hall conductance and its various generalizations…