arXiv subjects

J. Q. Zhang

Publications and source records attributed to J. Q. Zhang.

3 recordsLinked to original sources

arXiv2018

Ion-crystal demonstration of structural phase transition induced solely by temperature

We demonstrate for the first time a linear-zigzag phase transition induced solely by temperature of the $^{40}$Ca$^{+}$ ion crystals in a surface-electrode trap. In contrast to the previously observed counterparts based on change of the mechanical equilibrium conditions of the ions, our presented structural phase transition occurs due to controllable influence of thermal fluctuation. The ions' temperature is well controlled by tuning the cooling laser and the experimental observation could be fully understood by classical Langevin equation in addition to the effects from thermal fluctuation. Our experimental investigation indicates the fantastic role of thermal fluctuation played in the thermodynamic process at atomic level, which might bridge the thermodynamics from the macroscopic domain to the quantum regime.

quant-ph↗

arXiv2018

Single-atom demonstration of quantum Landauer principle

One of the outstanding challenges to information processing is the eloquent suppression of energy consumption in execution of logic operations. Landauer principle sets an energy constraint in deletion of a classical bit of information. Although some attempts have been paid to experimentally approach the fundamental limit restricted by this principle, exploring Landauer principle in a purely quantum mechanical fashion is still an open question. Employing a trapped ultracold ion, we experimentally demonstrate a quantum version of Landauer principle, i.e., an equality associated with energy cost of information erasure in conjunction with entropy change of the associated quantized environment. Our experimental investigation substantiates an intimate link between information thermodynamics and quantum candidate systems for information processing.

quant-ph↗

arXiv2002

Anomalous magnetic and electric moments of $τ$ and lepton flavor mixing matrix in effective lagrangian approach

In an effective lagrangian approach [EM97] to new physics, the authors in ref. [HL99] pushed tau anomalous magnetic and electric dipole moments (AMDM and EDM) down to $10^{-11}$ and $10^{-25} e cm$ by using a Fritzsch-Xing lepton mass matrix ansatz. In this note, we find that, in this approach, there exists the connection between $τ$ AMDM and EDM and the lepton flavor mixing matrix. By using the current neutrino oscillation experimental results, we investigate the parameter space of lepton mixing angles to $τ$ AMDM and EDM. We can obtain the same or smaller bounds of $δa_τ$ and $d_τ$ acquired in ref. [HL99] and constrain $θ_l$ (the mixing angle obtained by long-baseline neutrino oscillation experiments) from $τ$ AMDM and EDM.

hep-ph↗