arXiv subjects

Yong-Cong Chen

Publications and source records attributed to Yong-Cong Chen.

9 recordsLinked to original sources

arXiv2024

Entangled biphoton generation in myelin sheath

Consciousness within the brain hinges on the synchronized activities of millions of neurons, but the mechanism responsible for orchestrating such synchronization remains elusive. In this study, we employ cavity quantum electrodynamics (cQED) to explore entangled biphoton generation through cascade emission in the vibration spectrum of C-H bonds within the lipid molecules' tails. The results indicate that the cylindrical cavity formed by a myelin sheath can facilitate spontaneous photon emission from the vibrational modes and generate a significant number of entangled photon pairs. The abundance of C-H bond vibration units in neurons can therefore serve as a source of quantum entanglement resources for the nervous system. The finding may offer insight into the brain's ability to leverage these resources for quantum information transfer, thereby elucidating a potential source for the synchronized activity of neurons.

physics.bio-ph↗

arXiv2024

The light quantum mechanism of PCR efficiency oscillation with gold nanoparticle concentration

The widespread application of nanomaterials in polymerase chain reaction (PCR) technology has opened new avenues for improving detection methods in the biomedical field. Recent experiments (Chem. Eur. J. 2023, e202203513) have revealed oscillatory behavior between PCR efficiency and the concentration of gold nanoparticles in the pM range, potentially linked to the long-range Coulomb interactions among charged colloidal particles and the quantum size effect of nanoparticle electronic states. Through Monte Carlo simulation, we discovered that the radial distribution function of gold nanoparticles in solution gradually exhibits peak characteristics with increasing charge, triggering coherent photon behavior in Rayleigh scattering within the solution, thereby influencing the efficiency of reusing released photons in the PCR chain reaction. The study demonstrates that the oscillation period aligns with the wavelength of downstream reaction photons, while their energy matches the width of energy levels near the Fermi level of gold nanoparticles. The latter can absorb and store electron states internally, promoting upstream PCR reactions through subsequent re-release, and compensating for energy deficiencies through the Boltzmann distribution of electrons. This work is poised to advance the application of PCR-specific precise detection methods in the field of quantum biotechnology.

physics.bio-ph↗

arXiv2023

Hall anomaly by vacancies vs fragments of vortex lattice: Quantitative analyses of new evidences

Despite numerous recent studies on the Hall anomaly following the discovery of cuprate superconductivity, the origin of this phenomenon remains contentious. We demonstrate that a previously proposed mechanism, in which vacancy-on-fragment of the flux-line crystal, provides an alternative explanation for the observations of $\rm{Bi_{2}Sr_{2}CaCu_{2}O_{x}}$ thin films made by Nitzav and Kanigel [Phys. Rev. B. 107, 094516 (2023)], without the need for adjustable parameters. Specifically, we show that the power-law behavior of $\rho_{xy}$ over $\rho_{xx}$, with and without sign reversal, is consistent with the picture of vacancies versus fragments. Interestingly, we find that the effective length of vortex lines is consistently 1.5 unit cells (UC) across different experiments, independent of film thickness.

cond-mat.supr-con↗

arXiv2023

Stochastic Gradient Descent and Anomaly of Variance-flatness Relation in Artificial Neural Networks

Stochastic gradient descent (SGD), a widely used algorithm in deep-learning neural networks has attracted continuing studies for the theoretical principles behind its success. A recent work reports an anomaly (inverse) relation between the variance of neural weights and the landscape flatness of the loss function driven under SGD [Feng & Tu, PNAS 118, 0027 (2021)]. To investigate this seemingly violation of statistical physics principle, the properties of SGD near fixed points are analysed via a dynamic decomposition method. Our approach recovers the true "energy" function under which the universal Boltzmann distribution holds. It differs from the cost function in general and resolves the paradox raised by the the anomaly. The study bridges the gap between the classical statistical mechanics and the emerging discipline of artificial intelligence, with potential for better algorithms to the latter.

nlin.AO↗

arXiv2022

Topology, Vorticity and Limit Cycle in a Stabilized Kuramoto-Sivashinsky Equation

A noisy stabilized Kuramoto-Sivashinsky equation is analyzed by stochastic decomposition. For values of control parameter for which periodic stationary patterns exist, the dynamics can be decomposed into diffusive and transverse parts which act on a stochastic potential. The relative positions of stationary states in the stochastic global potential landscape can be obtained from the topology spanned by the low-lying eigenmodes which inter-connect them. Numerical simulations confirm the predicted landscape. The transverse component also predicts a universal class of vortex like circulations around fixed points. These drive nonlinear drifting and limit cycle motion of the underlying periodic structure in certain regions of parameter space. Our findings might be relevant in studies of other nonlinear systems such as deep learning neural networks.

nlin.AO↗

arXiv2022

Hall anomaly by vacancies in pinned lattice of vortices: A quantitative analysis on the thin-film data of BSCCO

Hall anomaly, as appears in the mixed-state Hall resistivity of type-II superconductors, has had numerous theories but yet a consensus on its origin. In this work, we conducted a quantitative analysis of the magnetotransport measurements on BSCCO thin films by Zhao et al. [Phys. Rev. Lett. 122, 247001 (2019)] and validate a previously proposed vacancy mechanism [cf. J. Phys. Condens. Matter. 10, L677 (1998)] with many-body vortex correlations for the phenomenon. The model attributes the Hall anomaly to the motion of vacancies in pinned fragments of vortex lattice. Its validity is first examined by an exploration on the vortex states near the Kosterlitz-Thouless transition on the vortex crystal. Comparisons are then carried out between the measured activation energies with the calculated creation energy of the vortex-anti-vortex pair and the vacancy energy on the flux-line lattice, with no adjustable parameter. Our analysis elucidates the theoretical basis and prerequisites of the vacancy model. In particular, the vacancy activation energies are an order of magnitude smaller than that of a sole vortex line. The proposed mechanism may provide a macro-theoretical framework for other studies.

cond-mat.supr-con↗

arXiv2018

Resonant confinement of excitonic polariton and ultra-efficient light harvest in artificial photosynthesis

We show that in the recent artificial light-harvesting experiment [Angewandte Chemie Intl. Ed. 55, 2759 (2016)] on organic nanocrystals self-assembled from difluoroboron chromophores, the spontaneous emission of an excited pigment should undergo a two-step process. It would first decay to an excitonic polariton confined by cavity resonance via strong photon-exciton coupling. The captive intermediate could then funnel the energy directly to doped acceptors, leading to the observed over 90% transfer efficiency at less than 1/1000 acceptor-donor ratio. Theoretical, parameter-free analyses are in quantitative agreement with the experiment.

physics.app-ph↗

arXiv1993

Optimizing the RVB state on a triangular lattice: Presence of the long-range order

We present a Schwinger-boson approach for the RVB state of the spin-1/2 Heisenberg antiferromagnet on a triangular lattice. It is shown that Gutzwiller projection of the mean-field state that includes both antiferromagnetic and ferromagnetic decouplings leads to optimizing the RVB pair amplitudes within a self-consistent approximation. The resulting state yields, by Monte Carlo simulations, energies and spin-spin correlations in excellent agreement with the exact diagonalization result on finite lattices (up to 36 sites). We conclude that the optimized RVB wavefunction possesses a long-range three-sublattice order.

cond-mat↗

arXiv1993

Optimized RVB states of the 2-d antiferromagnet: Ground state and excitation spectrum

The Gutzwiller projection of the Schwinger-boson mean-field solution of the 2-d spin-1/2 antiferromagnet in a square lattice is shown to produce the optimized, parameter-free RVB ground state. We get $-0.6688J$/site and $0.311$ for the energy and the staggered magnetization. The spectrum of the excited states is found to be linear and gapless near $\bk\cong 0$. Our calculation suggests, upon breaking of the rotational symmetry, $ε_{\bk}\cong 2JZ_{r} \sqrt{1-γ_{\bk}^{2}}$ with $Z_{r}\cong 1.23$. To appear in Phys. Lett. A (1993).

cond-mat↗