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Julian Juhi-Lian Ting

Publications and source records attributed to Julian Juhi-Lian Ting.

13 recordsLinked to original sources
arXiv2026

Asymmetric Textured Image Sensors Based on Antenna Theory as Designed by Nature

This work numerically validates the application of bio-inspired concepts on CMOS derived from bacterial photosynthetic light harvesters. We investigate a modification of symmetric inverted pyramid array CMOS image sensors into an asymmetrically shaped texture to explore the structural boundary of passive non-reciprocity. Diverging from traditional macroscopic continuum assumptions, we analyze whether structural asymmetry at sub-wavelength scales can induce non-reciprocal scattering under passive, linear, and time-invariant conditions. A theoretical framework based on perturbation theory is developed, estimating a potential efficiency enhancement of 5\% to 15\%. Numerical simulations performed via the MEEP finite-difference time-domain (FDTD) platform reveal that the linear response is highly localized, showing a subtle 0.02\% change. This suggests that macroscopic Lorentz reciprocity remains robust at the investigated scale due to apex field concentration, defining a clear geometric threshold for microscopic non-reciprocity.

physics.optics↗
arXiv2020

Fractal Interpretation of Bacterial Light Harvesters

Bacteria light harvesters are interpreted as Vicsek fractal, based upon their morphology, even though such fractals contain only one, or perhaps two, generations. After using fractal dimensions to describe the geometry, we progress to use connectivity matrices to make an improved description of the light harvesters and make connections with our previous studies.

physics.optics↗
arXiv2019

Non-reciprocal Light-harvesting Nanoantennae Made by Nature

Most of our current understanding of mechanisms of photosynthesis comes from spectroscopy. However, classical definition of radio-antenna can be extended to optical regime to discuss the function of light-harvesting antennae. Further to our previously proposed model of a loop antenna we provide several more physical explanations on considering the non-reciprocal properties of the light harvesters of bacteria. We explained the function of the non-heme iron at the reaction center, and presented reasons for each module of the light harvester being composed of one carotenoid, two short $α$-helical polypeptides and three bacteriochlorophylls; we explained also the toroidal shape of the light harvester, the upper bound of the characteristic length of the light harvester, the functional role played by the long-lasting spectrometric signal observed, and the photon anti-bunching observed. Based on these analyses, two mechanisms might be used by radiation-durable bacteria, {\it Deinococcus radiodurans}; and the non-reciprocity of an archaeon, {\it Haloquadratum walsbyi}, are analyzed. The physical lessons involved are useful for designing artificial light harvesters, optical sensors, wireless power chargers, passive super-Planckian heat radiators, photocatalytic hydrogen generators, and radiation protective cloaks. In particular it can predict what kind of particles should be used to separate sunlight into a photovoltaically and thermally useful range to enhance the efficiency of solar cells.

physics.bio-ph↗
arXiv2019

Dual-band Dielectric Light-harvesting Nanoantennae Made by Nature

Mechanisms to use nanoparticles to separate sunlight into photovoltaic useful range and thermally useful range to increase the efficiency of solar cells and to dissipate heat radiatively are discussed based upon lessons we learnt from photosynthesis. We show that the dual-band maxima in the absorption spectrum of bacterial light harvestors not only are due to the bacteriochlorophylls involved but also come from the geometry of the light harvestor. Being able to manipulate these two bands arbitrarily enables us to fabricate the nanoparticles required. Such mechanisms are also useful for the design of remote power charging and light sensors.

physics.optics↗
arXiv2018

Proposal for verifying dipole properties of light-harvesting antennas

For light harvesters with a reaction center complex (LH1-RC complex) of three types, we propose an experiment to verify our analysis based upon antenna theories that automatically include the required structural information. Our analysis conforms to the current understanding of light-harvesting antennae in that we can explain known properties of these complexes. We provide an explanation for the functional roles of the notch at the light harvester, a functional role of the polypeptide called PufX or W at the opening, a functional role of the special pair, a reason that the cross section of the light harvester must not be circular, a reason that the light harvester must not be spherical, reasons for the use of dielectric bacteriochlorophylls instead of conductors to make the light harvester, a mechanism to prevent damage from excess sunlight, an advantage of the dimeric form, and reasons for the modular design of nature. Based upon our analysis we provide a mechanism for dimerization. We predict the dimeric form of light-harvesting complexes is favoured under intense sunlight. We further comment upon the classification of the dimeric or S-shape complexes. The S-shape complexes should not be considered as the third type of light harvester but simply as a composite form.

physics.bio-ph↗
arXiv2003

Alternative Method for Quantum Feedback-Control

A new method for doing feedback control of single quantum systems was proposed. Instead of feeding back precisely the process output, a cloning machine served to obtain the feedback signal and the output. A simple example was given to demonstrate the method.

quant-ph↗
arXiv1999

Noise effects on One-Pauli Channels

The possibility of stochastic resonance of a quantum channel and hence the noise enhanced quantum channel capacity is explored by considering one-Pauli channels which are more classical like. The fidelity of the channel is also considered.

quant-ph↗
arXiv1999

Noise effects for the Depolarizing Channel

The possibility of stochastic resonance of a quantum channel and hence the noise enhanced capacity of the channel is explored by considering the depolarizing channel. The fidelity of the channel is also considered. Although there is no clear evidence for noise enhanced capacity found, there is enhancement for the fidelity for the depolarizing channel. PACS number(s): 05.40.-a, 03.67.Hk

cond-mat.stat-mech↗
arXiv1999

Stochastic resonance for quantum channels

The concept of stochastic resonance in nonlinear dynamics is applied to interpret the capacity of noisy quantum channels. The two-Pauli channel is used to illustrate the idea. The fidelity of the channel is also considered. Noise enhancement is found for the fidelity but not for the capacity.

quant-ph↗
arXiv1998

Driven Morse Oscillator: Model for Multi-photon Dissociation of Nitrogen Oxide

Within a one-dimensional semi-classical model with a Morse potential the possibility of infrared multi-photon dissociation of vibrationally excited nitrogen oxide was studied. The dissociation thresholds of typical driving forces and couplings were found to be similar, which indicates that the results were robust to variations of the potential and of the definition of dissociation rate. PACS: 42.50.Hz, 33.80.Wz

chao-dyn↗
arXiv1998

DNA Transcription Mechanism with a Moving Enzyme

Previous numerical investigations of an one-dimensional DNA model with an extended modified coupling constant by transcripting enzyme are integrated to longer time and demonstrated explicitly the trapping of breathers by DNA chains with realistic parameters obtained from experiments. Furthermore, collective coordinate method is used to explain a previously observed numerical evidence that breathers placed far from defects are difficult to trap, and the motional effect of RNA-polymerase is investigated.

solv-int↗
arXiv1994

Driven Morse Oscillator: Model for Multi-photon Dissociation of Nitrogen Oxide

Within a one-dimensional semi-classical model with a Morse potential the possibility of microwave multi-photon dissociation of vibrationally excited nitrogen oxide was studied. The dissociation thresholds of typical driving forces and couplings were found to be similar, which indicates that the results were robust to variations of the potential and the definition of dissociation rate.

cond-mat↗