Beyond "Oppenheimer"

Some reading for those who found the events of the film "Oppenheimer" interesting:

The Manhattan Project (and Before)

This is a concise timeline of the Manhattan project, from the initial atomic bomb patent (!) to the test of the Gadget. Beyond the science and the scientists at Los Alamos, the Manhattan Project was an incredible feat of engineering involving 129,000 workers at its peak, requiring the development of the first industrial-scale processes for the enrichment of uranium, generation of plutonium in nuclear reactors, and extraction and processing of enough fissile material required to build the bombs, all in less than 3 years! In wartime delays are much harder to stomach (compare with the case of ITER today).

The Taming of Plutonium: Pu Metallurgy and the Manhattan Project

This arXiv preprint outlines one of the unanticipated challenges arising during the Manhattan Project, that "plutonium would prove to be the most complex
element on the periodic table." At ambient pressure, plutonium exhibits six distinct solid allotropes (crystalline structures), more than any other element! The differing densities of the allotropes greatly complicated the processing of the plutonium into a bomb core, requiring the development of a suitable alloy to stabilize the plutonium into a single phase.

Trinity, by K. T. Bainbridge

A technical report outlining the organization of the first nuclear weapon test, practical challenges that emerged, and the data that was obtained.

Los Alamos and ‘‘Los Arzamas’’

A brief comparison between the American and Soviet nuclear weapons programs, the latter headed by Yulii Khariton who was sometimes called the Soviet Oppenheimer by his colleagues. But unlike Oppenheimer he remained the scientific director of the institute for more than 40 years.

The test of time: photonics

As we all (should) know, journal impact factor is a terrible measure of the quality of an individual article. What is more important than where an article is published is whether it has long lasting impact, and the only way to determine this for sure is to wait!

I used Web of Science to look at the most highly cited original research articles in photonics from ten years ago. Here are the top ten:

1. Photonic Floquet topological insulators (2142 citations)

This was the first work to experimentally demonstrate topological edge states in two-dimensional waveguide arrays. It was this (and related works below) which really popularized the now-booming field of topological photonics. While I'm not surprised to see it among the top articles from 2013, I wasn't expecting it to be number one!

2. Terahertz Metamaterials for Linear Polarization Conversion and Anomalous Refraction (1443 citations)

This work falls within two highly active fields: terahertz photonics and metasurfaces. Like other early works on metasurfaces (a few more appear below), the concepts were demonstrated using metallic structures. Ongoing commercialization today was enabled by the development of low loss all-dielectric metasurfaces over the following decade.

3. Photonic topological insulators (1306 citations)

This paper showed theoretically that photonic systems could be used to emulate quantum spin Hall topological phases, by using metamaterials with a judiciously-engineered magneto-electric coupling to emulate a fermionic time-reversal symmetry.

4. Imaging topological edge states in silicon photonics (1113 citations)

Experimental demonstration of a two-dimensional Chern insulator topological phase using ring resonator lattices. This platform is now used extensively for topological laser experiments and exploring other exotic topological tight binding models, including higher order topological phases.

5. Metasurface holograms for visible light (1094 citations)

6. Three-dimensional optical holography using a plasmonic metasurface (976 citations)

These articles published back-to-back in Nature Communications use the metasurface concept to create a hologram using a metallic film with a subwavelength thickness.

7. Wireless sub-THz communication system with high data rate (970 citations)

This work sagely foresaw that viral tiktok memes would drive demand for higher bandwidth mobile data. Higher bandwidth requires higher carrier frequencies, so here the authors demonstrate experimentally wireless data transmission at frequencies approaching the THz band. 

8. Photonic spin Hall effect at metasurfaces (917 citations)

Polarization-controlled beam deflection using a metallic metasurface.

9. Highly efficient gate-tunable photocurrent generation in vertical heterostructures of layered materials (912 citations)

10. Chip-integrated ultrafast graphene photodetector with high responsivity (889 citations)

The top ten is rounded out by two papers demonstrating that 2D materials including graphene can form the basis for highly efficient photodetectors.

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tl;dr: The most highly cited photonics papers in 2013 were on topological photonics, metasurfaces, terahertz and graphene.

Seeking quantum speedups using supersymmetric systems

There is a neat correspondence between the question of whether a simplicial complex has a k-dimensional hole and whether the ground state of a related supersymmetric (SUSY) quantum many-body Hamiltonian is at zero energy:

Complexity of Supersymmetric Systems and the Cohomology Problem

Clique Homology is QMA1-hard

A less technical presentation of the latter paper at QIP2023 and can be viewed here.

Both problems are QMA1-hard, meaning that the correctness of a trial solution can be efficiently checked by a quantum computer (but finding the correct solution remains hard even for the quantum computer). In contrast, recently-proposed quantum algorithms for TDA consider relaxations of the homology problem that can be solved efficiently using quantum algorithms, such as estimating the normalized number of k-cycles to some finite precision.

What other seemingly classical or purely mathematical problems can be naturally framed in the language of supersymmetric quantum mechanics? This promises to be fertile ground for exponential quantum speedups, and you don't need to be an expert in quantum algorithms to join the hunt!