solid light
{{Short description|Hypothetical solid form of light}}
{{About|2=the video game developer|3=Hardlight|4=the Spacey Jane song|5=Hardlight (song)|6=other uses|7=Hard light (disambiguation)}}
Solid light, or hard light, is a hypothetical material consisting of light in a solidified state. It primarily appears in science fiction.
It has been theorized that solid light could exist.{{cite web |url=https://www.sciencedaily.com/releases/2007/05/070506160623.htm |title=Could Light Behave As A Solid? A New Theory |website=ScienceDaily |author=University of Melbourne |date=7 May 2007 |access-date=30 January 2016}}{{cite journal | last1=Raftery | first1=J. | last2=Sadri | first2=D. | last3=Schmidt | first3=S. | last4=Türeci | first4=H. E. | last5=Houck | first5=A. A. | title=Observation of a Dissipation-Induced Classical to Quantum Transition | journal=Physical Review X | volume=4 | issue=3 | date=8 September 2014 | issn=2160-3308 | doi=10.1103/physrevx.4.031043 | page=031043| arxiv=1312.2963 | bibcode=2014PhRvX...4c1043R |doi-access=free}} Some experiments claim to have created solid photonic matter or molecules by inducing strong interaction between photons.{{cite web|last=Freeman|first=David|url=http://www.huffingtonpost.com/2014/09/16/solid-light-created_n_5824268.html |title=Scientists Say They've Created A Freaky New Form Of Light|website=The Huffington Post|date=16 September 2014|access-date=30 January 2016}}{{cite web|last=Reuell|first=Peter|url=http://news.harvard.edu/gazette/story/2013/09/seeing-light-in-a-new-way|title=Seeing light in a new way|website=Harvard Gazette|date=27 September 2013|access-date=30 January 2016}}{{cite web |last1=Chu |first1=Jennifer |title=Physicists create new form of light |url=https://news.mit.edu/2018/physicists-create-new-form-light-0215 |website=MIT News |date=15 February 2018 |access-date=2 January 2021}} Potential applications of solid light could include logic gates for quantum computers and room-temperature superconductor development.
A team of Italian scientists published in Nature Journal in March 2025 that they have found a way to make light act like a "supersolid".{{cite web |title=Scientists freeze light: Researchers discover a rare state of matter where it flows like liquid but holds shape like a solid - The Economic Times |url=https://m.economictimes.com/news/new-updates/scientists-freeze-light-researchers-discover-a-rare-state-of-matter-where-it-flows-like-liquid-but-holds-shape-like-a-solid/articleshow/118928851.cms |website=The Economic Times |access-date=13 March 2025 |date=12 March 2025}}{{Unreliable source|date=March 2025}}
Fiction
{{also|Holography in fiction}}
Solid light appears in several video game franchises, including Halo, Portal, and Overwatch. In Portal 2, sunlight is used to create "hard light bridges", which act as solid semi-transparent walkways or barriers.{{Cite web |title=Hard Light |url=https://tvtropes.org/pmwiki/pmwiki.php/Main/HardLight |access-date=2023-05-24 |website=TV Tropes}} In Overwatch, the fictional Vishkar Corporation uses solid light as a construction material. In Halo, solid light is the foundation of Forerunner weapons and many of their utilitarian devices like retractable bridges.{{CN|date=January 2024}}
Solid holograms appear many times in the TV show Star Trek.{{Cite web|url=https://www.startrek.com/article/meet-the-man-behind-the-holodeck-part-1|title=Meet the Man Behind the Holodeck, Part 1|date=25 July 2023 }} In Red Dwarf, the character Rimmer is a hologram who obtains a "hard light drive", allowing him to become tangible. In the animated show Steven Universe, several main characters are aliens who have physical forms made out of light, with a gemstone as the only material part of their body.{{Citation |title=The Classroom Gems: What Are Gems? {{!}} Steven Universe {{!}} Cartoon Network | date=18 November 2015 |url=https://www.youtube.com/watch?v=fOEScwq3slY |access-date=2024-02-05 |language=en}}{{Cite web |title=Steven Universe S1E24 "An Indirect Kiss" / Recap |url=https://tvtropes.org/pmwiki/pmwiki.php/Recap/StevenUniverseS1E24AnIndirectKiss |access-date=2024-02-05 |website=TV Tropes}}
In DC Comics' Green Lantern, the various Lantern Corps use solid light constructs. In Marvel Comics properties, "hard light" manifests in many forms. For example, Ms. Marvel utilizes photon blasts to generate concussive force.{{Cite web |title=Captain Marvel (Carol Danvers) Powers, Abilities, Villains {{!}} Marvel |url=https://www.marvel.com/characters/captain-marvel-carol-danvers/in-comics |access-date=2024-02-13 |website=www.marvel.com}} The X-Men's Danger Room also utilizes hard light constructs in its simulations.
Experiments
Photons, the particles that make up forms of electromagnetic radiation like light, do not normally interact with one another, but may be made to interact in a nonlinear medium.{{cite journal | last1=Firstenberg | first1=Ofer | last2=Peyronel | first2=Thibault | last3=Liang | first3=Qi-Yu | last4=Gorshkov | first4=Alexey V. | last5=Lukin | first5=Mikhail D. | last6=Vuletić | first6=Vladan | title=Attractive photons in a quantum nonlinear medium | journal=Nature | publisher=Springer Science and Business Media LLC | volume=502 | issue=7469 | date=25 September 2013 | issn=0028-0836 | doi=10.1038/nature12512 | pages=71–75| url=https://authors.library.caltech.edu/42032/7/nature12512-s1.pdf | pmid=24067613| bibcode=2013Natur.502...71F | hdl=1721.1/91605 | s2cid=1699899 | hdl-access=free }}
The MIT-Harvard Center for Ultracold Atoms conducted experiments on photon interaction in the 2010s. Single photons were fired from weak lasers into a dense cloud of rubidium cooled to near absolute zero. The speed of light in the cloud was about 100,000 times slower than in a vacuum. Within the cloud, photons lost energy and gained mass. The conditions allowed photons to attract and bind to other photons, and exit the cloud as molecules. Reportedly, photon pairs were observed in 2013, and triplets in 2018.