arXiv subjects

Y. -C. Huang

Publications and source records attributed to Y. -C. Huang.

4 recordsLinked to original sources

arXiv2025

Precursor to Quantum Criticality in Ce-Au-Al Quasicrystal Approximants

Rare-earth element containing aperiodic quasicrystals and their related periodic approximant crystals can exhibit non-trivial physical properties at low temperatures. Here, we investigate the 1/1 and 2/1 approximant crystal phases of the Ce-Au-Al system by studying the ac-susceptibility and specific heat at low temperatures and in magnetic fields up to 12 T. We find that these systems display signs of quantum criticality similar to the observations in other claimed quantum critical systems, including the related Yb-Au-Al quasicrystal. In particular, the ac-susceptibility at low temperatures shows a diverging behavior $χ\propto 1/T$ as the temperature decreases as well as cutoff-behavior in magnetic field. Notably, the field dependence of $χ$ closely resembles that of quantum critical systems. However, the ac-susceptibility both in zero and nonzero magnetic fields can be understood from the splitting of a ground state Kramers doublet of Ce$^{3+}$. The high-temperature Curie-Weiss fit yields an effective magnetic moment of approximately 2.54$μ_{\mathrm{B}}$ per Ce for both approximant systems, which is reduced to $\sim$2.0$μ_{\mathrm{B}}$ at temperatures below 10 K. The low-temperature specific heat is dominated by the Schottky anomaly originating from the splitting of the Ce$^{3+}$ Kramers doublet, resulting in an entropy of $R\ln 2$ at around 10 K.

cond-mat.str-el↗

arXiv2024

Quantum Critical Scaling of Specific Heat in a Quasicrystal

In strongly correlated systems, interactions give rise to critical fluctuations surrounding the quantum critical point (QCP) of a quantum phase transition. Quasicrystals allow the study of quantum critical phenomena in aperiodic systems with frustrated magnetic interactions. Here, we study the magnetic field and temperature scaling of the low-temperature specific heat for the quantum critical Yb-Au-Al quasicrystal. We devise a scaling function that encapsulates the limiting behaviors as well as the area where the system goes from a temperature-limited to a field-limited quantum critical region, where magnetic field acts as a cutoff for critical fluctuations. The zero-field electronic specific heat is described by a power-law divergence, ${C_{el}/T \propto T^{-0.54}}$, aligning with previously observed ac-susceptibility and specific heat measurements. The field dependence of the electronic specific heat at high magnetic fields shows a similar power-law ${C_{el}/T \propto B^{-0.50}}$. In the zero-field and low-field region, we observe two small but distinct anomalies in the specific heat, located at 0.7 K and 2.1 K.

cond-mat.str-el↗

arXiv2022

Laser excitation of the 1s-hyperfine transition in muonic hydrogen

The CREMA collaboration is pursuing a measurement of the ground-state hyperfine splitting (HFS) in muonic hydrogen ($μ$p) with 1 ppm accuracy by means of pulsed laser spectroscopy to determine the two-photon-exchange contribution with $2\times10^{-4}$ relative accuracy. In the proposed experiment, the $μ$p atom undergoes a laser excitation from the singlet hyperfine state to the triplet hyperfine state, {then} is quenched back to the singlet state by an inelastic collision with a H$_2$ molecule. The resulting increase of kinetic energy after the collisional deexcitation is used as a signature of a successful laser transition between hyperfine states. In this paper, we calculate the combined probability that a $μ$p atom initially in the singlet hyperfine state undergoes a laser excitation to the triplet state followed by a collisional-induced deexcitation back to the singlet state. This combined probability has been computed using the optical Bloch equations including the inelastic and elastic collisions. Omitting the decoherence effects caused by {the laser bandwidth and }collisions would overestimate the transition probability by more than a factor of two in the experimental conditions. Moreover, we also account for Doppler effects and provide the matrix element, the saturation fluence, the elastic and inelastic collision rates for the singlet and triplet states, and the resonance linewidth. This calculation thus quantifies one of the key unknowns of the HFS experiment, leading to a precise definition of the requirements for the laser system and to an optimization of the hydrogen gas target where $μ$p is formed and the laser spectroscopy will occur.

physics.atom-ph↗

arXiv2018

The next generation of laser spectroscopy experiments using light muonic atoms

Precision spectroscopy of light muonic atoms provides unique information about the atomic and nuclear structure of these systems and thus represents a way to access fundamental interactions, properties and constants. One application comprises the determination of absolute nuclear charge radii with unprecedented accuracy from measurements of the 2S$\,$-$\,$2P Lamb shift. Here, we review recent results of nuclear charge radii extracted from muonic hydrogen and helium spectroscopy and present experiment proposals to access light muonic atoms with $Z \geq 3$. In addition, our approaches towards a precise measurement of the Zemach radii in muonic hydrogen ($μ$p) and helium ($μ$$^{3}$He$^{+}$) are discussed. These results will provide new tests of bound-state quantum-electrodynamics in hydrogen-like systems and can be used as benchmarks for nuclear structure theories.

physics.atom-ph↗