NTT Research
Talks by Jess Riedel
Collaborative Knowledge Ratchets and Fermat's Library

Jess Riedel NTT Research

Luis Batalha Fermat's Library
Objective classical branch structure in a manybody wavefunction from spatial redundancy
When the wavefunction of a macroscopic system unitarily evolves from a lowentropy initial state, there is good circumstantial evidence it develops "branches", i.e., a decomposition into orthogonal components that can't be distinguished from the corresponding incoherent mixture by feasible observations, with each component a simultaneous eigenstate of preferred macroscopic observables. Is this decomposition unique? Can the number of branches decrease in time?
Symplectic covariant quantum Brownian motion: the harmonic oscillator of open systems
In the study of closed quantum system, the simple harmonic oscillator is ubiquitous because all smooth potentials look quadratic locally, and exhaustively understanding it is very valuable because it is exactly solvable. Although not widely appreciated, Markovian quantum Brownian motion (QBM) plays almost exactly the same role in the study of open quantum systems. QBM is ubiquitous because it arises from only the Markov assumption and linear Lindblad operators, and it likewise has an elegant and transparent exact solution.
Decoherence as a way to measure extremely soft collisions with Dark Matter
Quantum superpositions of matter are unusually sensitive to decoherence by tiny momentum transfers, in a way that can be made precise with a new diffusion standard quantum limit. Upcoming matter interferometers will produce unprecedented spatial superpositions of over a million nucleons. What sorts of dark matter scattering events could be seen in these experiments as anomalous decoherence? We show that it is extremely weak but medium range interaction between matter and dark matter that would be most visible, such as scattering through a Yukawa potential.