Jonathan Dowling (1955-2020)
By FRANCO NORI • Mar. 22, 2021 @ 18:06 GMT

In June 2020, the FQXi community lost Jonathan P. Dowling, who was Professor and Hearne Chair of Theoretical Physics at Louisiana State University (LSU). He was well known for his important work on quantum science and technology, particularly for exploiting quantum entanglement (in the form of a NOON state) for applications to quantum computing, quantum metrology, quantum sensing, and quantum imaging. He additionally greatly contributed to fields such as photonic band-gap structures, quantum optics, foundations of quantum mechanics, boson sampling, and quantum networks.

Dowling was also very well known for his very cheerful and playful style of communication, and he brightened up the lives of many students and colleagues throughout his stellar career. Science discussions with him were always great fun and quite memorable. His personal style made a very positive and unforgettable impression on very many scientists throughout the world. His untimely death (he was just 65 years young) shocked the quantum community around the world. Since last June, Dowling’s colleagues and friends have written an outpouring of condolences and support on social media. Dowling will be dearly missed by all the many people who had the fortune to meet him.


Unification of the four forces in the Spin11,1 geometric algebra by Andrew Hamilton
By ANDREW J S HAMILTON • Mar. 18, 2021 @ 13:57 GMT

The spinors of the group Spin(N) of rotations in N spacetime dimensions are indexed by a bitcode with [N/2] bits. A well-known promising grand unified group that contains the standard-model group is Spin(10). Fermions in the standard model are described by five bits durgb, consisting of two weak bits d and u, and three color bits r, g, b. If a sixth bit T is added, necessary to accommodate a time dimension, then the enlarged Spin(11,1) algebra contains the standard-model and Dirac algebras as commuting subalgebras, unifying all four forces. The largest subgroup of Spin(11,1) that commutes with the Poincare group is Spin(5)xSpin(6), suggesting that the latter is a partial unification on the way to complete unification in Spin(11,1). The Spin(5)xSpin(6) algebra contains a subalgebra with precisely the properties of the electroweak Higgs field. The Spin(5)xSpin(6) symmetry contains, and is spontaneously broken by, a U(1) symmetry related to the U_{B-L}(1) symmetry. Grand unification is associated with a change in the dimensionality of spacetime.

The talk addresses the ethics of responsible scientific refereeing.



Keywords: #GrandUnification


Semi-device-dependent benchmarking, certification, and tomography by Jens Eisert
By JENS EISERT • Mar. 16, 2021 @ 23:07 GMT

This talk explores in what sense one can meaningfully speak of semi-device-dependent benchmarking, certification, and tomography that strikes a balance between assuming perfect knowledge about detectors (which often is inappropriate) and no knowledge at all (which commonly is overly pessimistic). It also presents technical results along these lines, making use of a technical machinery of compressed sensing.



Keywords: #Informationasfuel #IAF


Tensor networks as a data structure by Jens Eisert
By JENS EISERT • Mar. 16, 2021 @ 23:05 GMT

This talk is concerned with tensor networks as a data structure in probabilistic modelling and for learning dynamical laws from data.



Keywords: #Informationasfuel


Tensor network methods augmented by mode transformations by Jens Eisert
By JENS EISERT • Mar. 16, 2021 @ 23:02 GMT

Tensor network methods augmented by mode transformations in molecular quantum chemistry and condensed matter physics (held in Dresden in March 2021).



Keywords: #tensornetwork

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