Masae Takahashi of the Department of Physics at Tohoku University has discovered that the strength of electron-phonon interactions within crystals is quantized and universally linked to the fine-structure constant, approximately equal to 1/137. This research, utilizing advanced terahertz spectroscopy to measure vibrational energies, reveals that electron-phonon coupling strength is always an integer multiple of the fine-structure constant multiplied by the Boltzmann constant, resulting in energy transfers of about one part in 137. This finding demonstrates a fundamental connection between the constant governing electromagnetic forces and the microscopic interactions between electrons and crystal lattices.
Quantized Electron-Phonon Coupling Strength
A recent discovery at Tohoku University reveals that electron-phonon coupling strength – the interaction between electrons and crystal vibrations – isn’t continuous, but quantized. Researchers found this strength is always a whole number multiple of a base unit. This unit is calculated by multiplying the fine-structure constant (approximately 1/137) by the Boltzmann constant, meaning roughly one part in 137 of the phonon’s energy transfers during each interaction. Advanced terahertz spectroscopy enabled precise measurement of these couplings.
This quantization links fundamental electromagnetic interactions, governed by the fine-structure constant, to the microscopic “dialogue” between electrons and crystals. The origin of this connection was traced to a process resembling Compton scattering, where electrons interact with photons emitted by phonons, not the phonons directly. This explains why the energy transfer scales with the fine-structure constant to the first power, a different result than what would be expected from spin-orbit interactions.
Understanding and quantifying these interactions has significant implications for material science. Electron-phonon interactions directly influence the performance of semiconductors, superconductors, and emerging quantum devices, offering potential for designing materials with tailored properties. The research, published in Chem. Phys. Impact on November 19, 2025, could also impact life sciences, as terahertz waves are known to influence cellular processes like division.
The Role of the Fine-Structure Constant
Research at Tohoku University has revealed a surprising connection between the fine-structure constant (α ≈ 1/137) and electron-phonon interactions within crystals. The study demonstrates that the strength of these interactions isn’t continuous, but quantized – occurring in integer multiples of a base unit. This unit is defined as the fine-structure constant multiplied by the Boltzmann constant, meaning approximately one part in 137 of the phonon’s energy transfers during each interaction.
This discovery links a fundamental constant governing electromagnetic forces to the microscopic interactions between electrons and crystal lattices. Researchers used terahertz spectroscopy to precisely measure electron-phonon coupling, finding that energy transfer scales with α to the first power—a result explained by electrons colliding with photons emitted by phonons, rather than direct electron-phonon collisions. This process resembles Compton scattering.
The implications of this finding extend to material science and potentially life sciences. By quantifying these interactions, scientists can design materials with tailored properties, improving the performance of semiconductors, superconductors, and quantum devices. This universal quantum rule, connecting electromagnetic forces to crystal vibrations, could influence innovations in electronics and beyond, impacting technologies like smartphones, computers, and even future biological applications.
This work shows that even the whispers between electrons and crystals follow the universal language of quantum constants.
Masae Takahashi
Terahertz Spectroscopy and Measurement Precision
Advanced terahertz spectroscopy was instrumental in achieving unprecedented precision when measuring electron-phonon coupling strength. This technique probes vibrations within the energy range between infrared and microwaves, allowing researchers to quantify interactions between electrons and lattice vibrations inside crystals. The study revealed this coupling strength isn’t continuous, but instead occurs in integer multiples of a base unit linked to the fine-structure constant (α ≈ 1/137) and the Boltzmann constant.
The research demonstrates that approximately one part in 137 of the phonon’s energy is transferred during each electron-phonon interaction. This finding is significant because it establishes a connection between a fundamental constant governing electromagnetic forces – the fine-structure constant – and microscopic interactions within crystals. The observed energy transfer scales with α to the first power, differing from spin-orbit interactions which would scale with α².
Quantifying these interactions through precise terahertz spectroscopy has implications for materials science. Understanding electron-phonon coupling is key to designing materials with tailored properties for applications like faster electronics, more efficient energy technologies, and next-generation quantum devices. The study, published in Chem. Phys. Impact on November 19, 2025, adds new information to well-established quantum mechanics.
