Quasiparticles & collective excitations as a research area investigates emergent, effective degrees of freedom in many-body systems, where interactions among underlying microscopic constituents give rise to particle-like or mode-like entities such as phonons, magnons, polarons, excitons, and plasmons. This field focuses on formulating and analyzing low-energy effective theories, dispersion relations, lifetimes, and interaction vertices of these excitations using frameworks such as many-body perturbation theory, Green’s functions, field-theoretic methods, and numerical many-body techniques. It plays a central role in understanding transport, superconductivity, topological phases, and nonequilibrium dynamics in condensed matter, ultracold atomic systems, and related quantum materials.
Excitons, bound states between an electron (i.e., a negatively charged particle) and a hole (i.e., the absence of an electron) in materials, are a key focus of condensed matter physics studies. These bound states can give ...
Caltech scientists have developed an artificial intelligence (AI)–based method that dramatically speeds up calculations of the quantum interactions that take place in materials. In new work, the group focuses on interactions ...
Condensed Matter
Sep 16, 2025
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209
This is what fun looks like for a particular set of theoretical chemists driven to solve extremely difficult problems: Deciding whether the electromagnetic fields in molecular polaritons should be treated classically or quantum ...
Quantum Physics
Sep 15, 2025
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255
A new nanostructure acts like a wire and switch that can, for the first time, control and direct the flow of quantum quasiparticles called excitons at room temperature.
Nanophysics
Sep 11, 2025
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73
Polaritons are quasiparticles emerging from strong interactions between light particles (i.e., photons) and matter excitations (e.g., excitons). Over the past few years, researchers have found that these quasiparticles can ...
Magnetization switching remains one of the central applications of spintronic devices.
Nanophysics
Aug 26, 2025
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36
Scientists have long speculated that polaritons—hybrids of light and matter—could be harnessed to control photochemistry. Now, researchers at the City University of New York (CUNY) have shown that these fleeting states can ...
Nanophysics
Aug 21, 2025
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86
Polaritons are formed by the strong coupling of light and matter. When they mix together, all the matter is excited simultaneously—referred to as delocalization. This delocalization has the unique ability to relay energy ...
Optics & Photonics
Aug 21, 2025
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47
The ability to move electron-hole pairs—called excitons—in desired directions is important for generating electricity and creating fuels. This happens naturally in photosynthesis, making it a source of inspiration to researchers ...
Condensed Matter
Aug 14, 2025
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69
In a new study published in Nature Physics, scientists have achieved the first experimental observation of phonon angular momentum in chiral crystals.
