In recent years, certain metals have been found that do not obey traditional electric conventions. This article touches upon the concept of ‘strange metals’, what makes them unique, and their relation with black holes, and shows how they confuse the traditional quantum theory rules. It also gives an insight into the potential research work carried out in the field and the discoveries it might facilitate in other domains.
Image Credit: Philipp Tur/Shutterstock.com
What are Strange Metals?
To understand how strange metals work, one needs to understand how normal metals react to changes in temperature. In normal metals, the resistance of the metal increases with the square of the temperature. However, this rule is not followed by strange metals, whose electrical resistance increases linearly in relation to temperature.
Due to this, strange metals tend to act as superconductors at higher temperatures and this leads to them having no resistance at these temperatures. This means that they have electrical conductivity even at higher temperatures. Strange metals were found around 30 years ago in materials called cuprates.
The Uniqueness of Strange Metals
Strange metals, as appropriately named, exhibit strange conductive properties that do not follow traditional metal definitions. Due to the electrical resistance being linked directly with the temperature, strange metals lose their energy as fast as the law of quantum mechanics allows. Their conductivity has also been linked to two parameters, namely Planck’s constant and Boltzmann’s constant, which relate to photon energy and kinetic energy, respectively.
Relation with Black Holes
Perhaps the most intriguing part of studying strange metals is that they seem to display similar properties to that of a black hole. The concepts of Planck’s constant and Boltzmann’s constant, both of which have a direct relationship with the conductivity of a strange metal, also happen to be parameters associated with describing one of the most intriguing phenomena in the universe: a black hole.
Therefore, to understand strange metals, scientists have been using mathematical approaches that are similar to those that are used to study black holes.
Challenging Quantum Theory
Despite having a direct relationship between three parameters, namely Planck’s constant, Boltzmann’s constant, and conductivity, it has still been difficult to model the properties of strange metals. The main question that is puzzling scientists is the ability of the metals to challenge the elements of quantum theory.
These Strange Metals Could Make Electronics Perfectly Efficient
Video Credit: Seeker/Youtube.com
Dr. Valles and his research team from Brown University have been working on determining how strange metals carry an electric charge. Their research shows that ‘wave-like’ entities called Cooper pairs are carrying electric charge in these metals instead of traditional elections.
These Cooper pairs, found by Nobel Laureate Leon Cooper in 1952, act like a bosonic system. A bosonic system rarely interacts with other elements. Examples include photons and hydrogen. It was found out that Cooper pair bosons exhibit metallic behavior, where they can conduct electricity with some amount of resistance. This phenomenon went against the quantum theory and completely surprised the research team.
Further in their study, the team induced a Cooper-pair metallic state using a cuprate material called yttrium barium copper oxide which was patterned with tiny holes. The developed material was cooled just above the superconducting temperature and changes in its conductance were observed. The results found out that like fermionic strange metals, the conductance of a cooper-pair metal is linear with temperature.
Decoding strange metals would have a massive impact in the field of metals as it holds the key to understanding high superconductivity in metals. This would be very useful for lossless power grids, as we might finally find a way to transfer power from one place to another without any waste. Also, this would be very useful in improving supercomputers since they rely on them for faster computation rather than traditional qubits and gates.
Also, due to having similar properties to black holes, strange metals could be a gateway to unlock further secrets of the universe, possibly opening doors to its basic fundamental components.
References and Further Reading
Yang, C., Liu, H., Liu, Y. et al. Signatures of a strange metal in a bosonic system. Nature 601, 205–210 (2022). https://doi.org/10.1038/s41586-021-04239-y
Landau Theory of the Fermi Liquid 5.1 Adiabatic Continuity. (n.d.). [online] Available at: http://eduardo.physics.illinois.edu/phys561/FL.pdf.
Linear resistivity and Sachdev-Ye-Kitaev (SYK) spin liquid behavior in a quantum critical metal with spin-1/2 fermions
Peter Cha, Nils Wentzell, Olivier Parcollet, Antoine Georges, Eun-Ah Kim Proceedings of the National Academy of Sciences Aug 2020, 117 (31) 18341 18346; DOI: 10.1073/pnas.2003179117
Boson systems. (n.d.). [online] Available at: https://ocw.mit.edu/courses/physics/8-08-statistical-physics-ii-spring-2005/lecture-notes/fieldtheory_bos.pdf.