A new study examined how quantum critical metals, which behave unusually under low temperatures, challenge conventional physics theories.
The research reveals that these metals experience significant changes at quantum critical points, potentially informing the development of high-temperature superconductors.
Strange Metals and Quantum Fluctuations
A recent study led by Rice University physicist Qimiao Si sheds light on the mysterious behavior of quantum critical metals — materials that break the usual rules of physics at low temperatures. Published on December 9 in Nature Physics, the research explores quantum critical points (QCPs), where materials hover between two distinct states, such as being magnetic or nonmagnetic. These findings help explain the unique properties of these metals and offer new insights into high-temperature superconductors, which conduct electricity without resistance at relatively high temperatures.
At the heart of the study is quantum criticality, a state where materials become extremely sensitive to quantum fluctuations — tiny disruptions that change how electrons behave. While most metals follow well-established physical laws, quantum critical metals defy these expectations, displaying unusual and collective behaviors that have puzzled scientists for decades. Physicists refer to these systems as “strange metals.”
Role of Quasiparticles in Quantum Metals
“Our work dives into how quasiparticles lose their identity in strange metals at these quantum critical points, which leads to unique properties that defy traditional theories,” said Si, the Harry C. and Olga K. Wiess Professor of Physics and Astronomy and director of Rice’s Extreme Quantum Materials Alliance.
Quasiparticles, representing the collective behavior of electrons acting like individual particles, play a crucial role in energy and information transfer in materials. However, at QCPs, these quasiparticles vanish in a phenomenon known as Kondo destruction. Here magnetic moments in the material cease their usual interaction with electrons, dramatically transforming the metal’s electronic structure.
This change is evident in the Fermi surface, a map of possible electron states within the material. As the system crosses the QCP, the Fermi surface abruptly shifts, significantly altering the material’s properties.
Exploring Universal Behaviors
The study extends beyond heavy fermion metals — materials with unusually heavy electrons — to include copper oxides and certain organic compounds. All of these strange metals exhibit behaviors that defy traditional Fermi liquid theory, a framework used to describe electron motion in most metals. Instead, their properties align with fundamental constants such as Planck’s constant, governing the quantum relationship between energy and frequency.
Implications for Advanced Superconductors
The researchers identified a condition called dynamical Planckian scaling, where the temperature dependence of electronic properties mirrors universal phenomena like cosmic microwave background radiation and the radiation of the “black body” that approximates the behavior of stars. This discovery underscores a shared organizational pattern across various quantum critical materials, offering insights into creating advanced superconductors.
Quantum Transitions in New Materials
The research implications extend to other quantum materials, including iron-based superconductors and those with intricate lattice structures. One example is CePdAl, a compound where the interplay of two competing forces — the Kondo effect and RKKY interactions — determines its electronic behavior. By studying these transitions, scientists hope to decode similar phenomena in other correlated materials, where complex interelectronic relationships dominate.
Observing how these forces shape the material at QCPs could help scientists better understand transitions in other correlated materials or those with complex interelectronic relationships.
Reference: “Quantum critical metals and loss of quasiparticles” by Haoyu Hu, Lei Chen and Qimiao Si, 9 December 2024, Nature Physics.
DOI: 10.1038/s41567-024-02679-7
This research, co-authored by Haoyu Hu and Lei Chen from Rice’s Department of Physics and Astronomy, Extreme Quantum Materials Alliance and Smalley-Curl Institute, was supported by the National Science Foundation, Air Force Office of Scientific Research, Robert A. Welch Foundation, Vannevar Bush Faculty Fellowship and European Research Council.
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2 Comments
The work of researchers dives into how quasiparticles lose their identity in strange metals at these quantum critical points, which leads to unique properties that defy traditional theories.
Please ask the researchers to think deeply:
What is the spacetime background of the quasiparticles and quantum critical points?
Scientific research guided by correct theories can help people avoid detours, failures, and exaggeration. The physical phenomena observed by researchers in experiments are always appearances, never the natural essence of things. The natural essence of things needs to be extracted and sublimated based on mathematical theories via appearances , rather than being imagined arbitrarily.
Everytime scientific revolution, the scientific research space brought by the new paradigm expands exponentially. Physics should not ignore the analyzable physical properties of topological vortices.
(1) Traditional physics: based on mathematical formalism, experimental verification and arbitrary imagination.
(2) Topological Vortex Theory (TVT): Although also based on mathematics (such as topology), it focuses more on non intuitive geometry and topological structures, challenging traditional physical intuition.
Topological Vortex Theory (TVT) points out the limitations of the Standard Model in describing the large-scale structure of the universe, proposes the need to consider non-standard model components such as dark matter and dark energy, and suggests that topological vortex fields may be key to understanding these phenomena. Topological vortex theory (TVT) heralds innovative technologies such as topological electronics, topological smart batteries, topological quantum computing, etc., which may bring low-energy electronic components, almost inexhaustible currents, and revolutionary computing platforms, etc.
Topology tells us that topological vortices and antivortices can form new spacetime structures via the synchronous effect of superposition, deflection, or twisting of them. Mathematics does not tell us that there must be God particles, Devil particles, Fermions, or Bosons present. When physics and mathematics diverge, arbitrary imagination will make physics no different from theology. Topological vortex research reflections on the philosophy and methodology of science help us understand the nature essence of science and the limitations of scientific methods. This not only has guiding significance for scientific research itself, but also has important implications for science education and popularization.
All things follow certain laws, which can be revealed through observation and research ( such as topological structures ). Today, so-called academic publications (such as PRL, Nature, Science, etc.) obstinately believe that two sets of cobalt 60 rotating in opposite directions can become two mirror images of each other. This is a public humiliation to the normal intelligence of the public. They conducted extensive pseudo scientific research based on CP violations, published countless pseudo scientific papers, and received various awards. The so-called scientific evaluation system constructed based on these so-called academic publications opened the dirtiest, ugliest, and most evil era in the history of modern science. They hardly know what shame is.
Please witness the exemplary collaboration between theoretical physicists and experimentalists (https://scitechdaily.com/microscope-spacecrafts-most-precise-test-of-key-component-of-the-theory-of-general-relativity/#comment-854286). It is normal to make mistakes in scientific research, but what is abnormal is to stubbornly adhere to erroneous positions and not repent.
Let us continue to witness via facts the dirtiest and ugliest era in the history of sciences and humanities in human society. The laws of nature will not change due to misleading of certain so-called academic publications or endorsements from certain so-called scientific awards.
As some comments have stated ( https://scitechdaily.com/super-photons-unveiled-sculpting-light-into-unbreakable-communication-networks/#comment-861546 ): Fortunately, we have enough pieces to put the puzzle together properly, and there are folks who have chosen to forego today’s societal structures in order to do exactly that.
Additionally, some comments have stated ( https://scitechdaily.com/science-made-simple-what-is-nuclear-fission/#comment-862083 ): You have been spewing this type of nonsensical word salad for several years now. Outrage doesn’t equal competence. If anything, your inability to convince anyone is a sign of your incompetence. Ask the commenter：Today, so-called official (such as PRL, Nature, Science, etc.) in physics stubbornly believes that two sets of cobalt-60 rotating in opposite directions can become two sets of objects that mirror each other, and it even won awards. These so-called academic publications have the audacity to blatantly talk nonsense in public. Do you think this is personal misfortune or misfortune of humanity?
My repetition may make some people feel disgusted ( https://scitechdaily.com/spooky-action-at-ultra-short-distances-unlocking-the-quantum-core-of-matter/#comment-866750 ). Nevertheless, in order to oppose rampant pseudoscience, I can only do so.
Isn’t this the evil consequence of the Physics Review family misleading science? Academic circle is not Entertainment industry. Have some people really never know what shame is?
Is traditional theory scientific? What is the difference between science and pseudoscience? Anyone who dares to share their ideas with the world should not be afraid of being repeatedly commented on.
Topological spins create everything, topological spins shape the world.
If anyone is interested in science, they can browse https://zhuanlan.zhihu.com/p/4659236468.