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Kuyukov V. abakan: "Holography and time" in Tensor networks as a data...

Lungani : "I Everyone I'm New here it an honour to be here and join you to share our..." in Why Time Might Not Be an...

Lungani : "I Everyone I'm New here it an honour to be here and join you to share our..." in Why Time Might Not Be an...

Steve Dufourny: "Hi Mr Schindler , I d like to explain you something, sorry to be off topic,..." in Tensor networks as a data...

Steve Dufourny: "It is very important this general idea and I need help of mathematicians to..." in Alternative Models of...

Steve Dufourny: "My intuitive equation considering the cold dark matter encoded in nuclei..." in Alternative Models of...

Jack James: "I noticed this was a 4 dimensional approach also. ..." in Unification of the four...

Anonymous: "good to read this post" in The Noise of Gravitons

click titles to read articles

Can Choices Curve Spacetime?
Two teams are developing ways to detect quantum-gravitational effects in the lab.

The Quantum Engine That Simultaneously Heats and Cools
Tiny device could help boost quantum electronics.

The Quantum Refrigerator
A tiny cooling device could help rewrite the thermodynamic rule book for quantum machines.

Time to Think
Philosopher Jenann Ismael invokes the thermodynamic arrow of time to explain how human intelligence emerged through culture.

Lockdown Lab Life
Grounded physicists are exploring the use of online and virtual-reality conferencing, and AI-controlled experiments, to maintain social distancing. Post-pandemic, these positive innovations could make science more accessible and environmentally-friendly.

April 18, 2021

New Blog Entries
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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.
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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
26 comments | view comments

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
83 comments | view comments

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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Recent Blog Entries

Measuring the number of photons in a microwave...
Counting the number of photons in an electromagnetic mode is an important tool for quantum information processing. In order to perform a single shot measurement, one usually encodes information about the photon number into a qubit state and read out...
March 16th, 2021 | -1 comments | view blog entry & comments

Scaling Down the Laws of Thermodynamics by Chris...
Thermodynamics provides a robust conceptual framework and set of laws that govern the exchange of energy and matter. Although these laws were originally articulated for macroscopic objects, nanoscale systems also exhibit “thermodynamic-like”...
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Learning time: clocks and analogue machine...
General-purpose analogue machine learning has a history that predates digital computing with the first important results published by Shannon in 1941. In this talk, I discuss the thermodynamics constraints on analogue machine learning based on Hopf...
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Measuring and tuning quantum devices faster than...
Machine learning has been the enabler of well-known breakthroughs in computer science, such as the victory of Alpha Go over a Go world champion and superhuman face recognition. I will show you how we can direct this great potential to the...
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January 1st, 1970 | -2 comments | view blog entry & comments

Is Quantum Theory exact? Exploring Quantum...
I organized and chaired an online workshop between 10-11 December 2020, where participants discussed the possible boundaries and limits of validity of quantum mechanics theory and implications of this research in various sectors, including the...
March 1st, 2021 | 51 comments | view blog entry & comments

The energetic cost of work extraction by Alexia...
We analyze work extraction from a qubit into a wave guide (WG) acting as a battery, where work is the coherent component of the energy radiated by the qubit. The process is stimulated by a wave packet whose mean photon number (the battery's charge)...
December 19th, 2020 | 5 comments | view blog entry & comments

Thermodynamics beyond the weak coupling limit:...
A key assumption in the standard thermodynamic description of macroscopic systems is that the system’s interaction with its environment is very weak and can be neglected. For microscopic systems, however, this assumption breaks down. In this talk I...
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Multi time point (thermodynamic) constraints for...
Standard thermodynamics deals with initial and final states and not much is known on what happens in between. By extending the notion of passivity to periodically driven systems, we obtain constraints on the dynamics under periodic...
December 17th, 2020 | -1 comments | view blog entry & comments

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