Scientific Series

How do the density profiles of dark matter halos emerge from their hierarchical assembly? We address this question using the Boltzmann–Poisson equations for the evolution of the coarse-grained distribution function of a halo composed of subhalos with a continuous mass spectrum in an expanding…

This talk is about the proposal that (1) quantum states that violate the momentum and Hamiltonian constraints represent instances of time, and (2) time evolution corresponds to the gradual collapse of an initial state toward a diffeomorphism-invariant state, driven by stochastic fluctuations of the…

Quasinormal-mode frequencies are characteristic frequencies of a black hole spacetime, and can be detected using gravitational waves. The measurement of these frequencies is used to test the nature of astrophysical black holes. However, the quasinormal-mode spectrum is unstable. The spectral…

The Cosmological Principle, which assumes that the Universe is homogeneous and isotropic on large scales, is one of the foundations of the standard model of cosmology. One of its consequences is that the cosmic microwave background (CMB) dipole is due to our motion, rather than being an intrinsic…

Applying for postdoc positions? Or thinking about applying next year? Join this panel discussion to hear advice on preparing a strong application. Panelists will include Perimeter's Grants and Awards Officer, as well as postdocs with experiences across different research areas, institutions, and…

Two-dimensional topological order has caught much attention in connection to topological phases of matter and topological quantum computation, in particular. It is known that tensor networks are useful tools to study mathematical structures appearing in these topics. We present recent understanding…

One of the main achievements of my last four years at Perimeter has been the development and formulation of intrinsic null geometry. This framework has served as a common denominator for the study of the (algebraic) quantization of gravity on null hypersurfaces; connections to quantum-gravity…

In this work-in-progress, we study the quantization of singular configuration spaces, generalizing the canonical structures of smooth quantum mechanics. We develop a framework for constructing a Hilbert space of quantum states, generalized position and momentum operators, a kinetic-plus-potential…

Any quantum system can be closely approximated by a quantum circuit with spatially-localized qubits. We analyze such quantum circuits and present evidence that the local weak values comprise a covariant tensor associated with each individual qubit. Even if the state is massively entangled, these…

As quantum processors scale, robust and scalable tools to characterize gate-level noise become indispensable. Randomized benchmarking (RB) and its many variants have emerged as the go-to protocols in practice: they yield a single number to characterize a gate set, the average gate fidelity, per…

The assignment of scattering data to monopoles is a classical construction in gauge theory useful to understand the geometry of monopole moduli spaces; from the modern perspective, it is of interest because monopole scattering matrices are quasiclassical limits of R-matrices of shifted Yangians. I…