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Ran Huang

Publications and source records attributed to Ran Huang.

At least 37 records · Page 2Linked to original sources

Thermodynamics of Ising Antiferromagnets with Phantom Cross-link Network on Husimi Lattice

A second order cross-linked network is applied onto the classical Husimi lattice, to investigate the role of a "phantom" non-neighboring interactions of mid- and long-range in Bethe-like lattices for the first time. Since antiferromagnetic Ising model on Husimi lattice has been exactly solved and successfully presented the melting and glass transition, the Phantom Cross-link Network (PCN) is introduced here to understand the relationship between glassy defect and long-range interactions in small molecule systems, and the concept is inspired from the classical rubber network theory (Flory, 1985). One random site out of four on the recursive unites with certain distance I (the net size) is selected to be linked onto the PCN. The solutions are still in the fashion of normal antiferromagnetic Ising model, with expected frustrations along with the net size I. Beside the regular Curie transition, several interesting thermodynamics are observed in this toy model, and as the main found, PCN clearly introduces glassy portion into the system, identified by the supercooling behavior with lower TC, the metastable entropy curve and the Kauzmann paradox.

cond-mat.stat-mech↗

Cubic singularities in binary linear electromechanical oscillators

Singularities arise in diverse disciplines and play a key role in both exploring fundamental laws of physics and making highly-sensitive sensors. Higher-order (>3) singularities, with further improved performance, however, usually require exquisite tuning of multiple (>3) coupled degrees of freedom or nonlinear control, thus severely limiting their applications in practice. Here we propose theoretically and confirm using mechanics experiments that, cubic singularities can be realized in a coupled binary system without any nonlinearity, only by observing the phase tomography of the driven response. By steering the cubic phase-tomographic singularities in an electrostatically-tunable micromechanical system, enhanced cubic-root response to frequency perturbation and voltage-controlled nonreciprocity are demonstrated. Our work opens up a new phase-tomographic method for interacted-system research and sheds new light on building and engineering advanced singular devices with simple and well-controllable elements, with a wide range of applications including precision metrology, portable nonreciprocal devices, and on-chip mechanical computing.

physics.app-ph↗

Nonlinear multi-frequency phonon lasers with active levitated optomechanics

Phonon lasers, exploiting coherent amplifications of phonons, have been a cornerstone for exploring nonlinear phononics, imaging nanomaterial structures, and operating phononic devices. Very recently, by levitating a nanosphere in an optical tweezer, a single-mode phonon laser governed by dispersive optomechanical coupling has been demonstrated, assisted by alternating mechanical nonlinear cooling and linear heating. Such levitated optomechanical (LOM) devices, with minimal noises in high vacuum, can allow flexible control of large-mass objects without any internal discrete energy levels. However, untill now, it is still elusive to realize phonon lasing with levitated microscale objects, due to much stronger optical scattering losses. Here, by employing a Yb3+-doped active system, we report the first experiment on nonlinear multi-frequency phonon lasers with a micro-size sphere governed instead by dissipative LOM coupling. In this work, active gain plays a key role since not only 3-order enhancement can be achieved for the amplitude of the fundamental-mode phonon lasing, compared with the passive device, but also nonlinear mechanical harmonics can emerge spontaneously above the lasing threshold. Furthermore, for the first time, coherent correlations of phonons are observed for both the fundamental mode and its harmonics. Our work drives the field of LOM technology into a new regime where it becomes promising to engineer collective motional properties of typical micro-size objects, such as atmospheric particulates and living cells, for a wide range of applications in e.g., acoustic sensing, gravimetry, and inertial navigation.

physics.optics↗

Loss-Induced Quantum Revival

Conventional wisdom holds that quantum effects are fragile and can be destroyed by loss. Here, contrary to general belief, we show how to realize quantum revival of optical correlations at the single-photon level with the help of loss. We find that, accompanying loss-induced transparency of light in a nonlinear optical-molecule system, quantum suppression and revival of photonic correlations can be achieved. Specifically, below critical values, adding loss into the system leads to suppressions of both optical intensity and its non-classical correlations; however, by further increasing the loss beyond the critical values, quantum revival of photon blockade (PB) can emerge, resulting in loss-induced switch between single-PB and two-PB or super-Poissonian light. Our work provides a strategy to reverse the effect of loss in fully quantum regime, opening up a counterintuitive route to explore and utilize loss-tuned single-photon devices for quantum technology.

quant-ph↗

Breaking Anti-$\mathcal{PT}$ Symmetry by Spinning a Resonator

Non-Hermitian systems, with symmetric or antisymmetric Hamiltonians under the parity-time ($\mathcal{PT}$) operations, can have entirely real eigenvalues. This fact has led to surprising discoveries such as loss-induced lasing and topological energy transfer. A merit of anti-$\mathcal{PT}$ systems is free of gain, but in recent efforts on making anti-$\mathcal{PT}$ devices, nonlinearity is still required. Here, counterintuitively, we show how to achieve anti-$\mathcal{PT}$ symmetry and its spontaneous breaking in a linear device by spinning a lossy resonator. Compared with a Hermitian spinning device, significantly enhanced optical isolation and ultrasensitive nanoparticle sensing are achievable in the anti-$\mathcal{PT}$-broken phase. In a broader view, our work provides a new tool to study anti-$\mathcal{PT}$ physics, with such a wide range of applications as anti-$\mathcal{PT}$ lasers, anti-$\mathcal{PT}$ gyroscopes, and anti-$\mathcal{PT}$ topological photonics or optomechanics.

physics.optics↗

Development of readout electronics a novel beam monitoring system for ion research facility accelerator

This article presents the readout electronics of a novel beam monitoring system for ion research facility accelerator. The readout electronics are divided into Front-end Card (FEC) and Readout Control Unit (RCU). FEC uses Topmetal II minus to processes the energy of the hitting particles and convert it into a voltage signal. The main function of RCU is to digitize the analog output signal of FEC and format the raw data. On the other hand, the RCU also processes the control commands from the host and distributes the commands according to the mapping. The readout electronic has been characterized and calibrated in the laboratory, and have been installed with the detector. Implementation and testing of readout electronics have been discussed.

physics.ins-det↗

The nanosphere phonon laser

A phonon laser made from a levitated silica nanosphere held in a controllable optical trap offers a useful tool for studying phonon-photon interactions.

quant-ph↗

Nonreciprocal unconventional photon blockade in a spinning optomechanical system

We propose how to achieve quantum nonreciprocity via unconventional photon blockade (UPB) in a compound device consisting of an optical harmonic resonator and a spinning optomechanical resonator. We show that, even with an extremely weak single-photon nonlinearity, nonreciprocal UPB can emerge in this system, i.e., strong photon antibunching can emerge only by driving the device from one side, but not from the other side. This nonreciprocity results from the Fizeau drag, leading to different splitting of the resonance frequencies for the counter-circulating modes. Such nonreciprocal quantum UPB devices can be particularly useful in achieving e.g., few-photon diodes or circulators, and quantum chiral photonic engineering.

quant-ph↗

Phase transitions of antiferromagnetic Ising spins on the zigzag surface of an asymmetrical Husimi lattice

An asymmetrical 2D Ising model with a zigzag surface, created by diagonally cutting a regular square lattice, has been developed to investigate the thermodynamics and phase transitions on surface by the methodology of recursive lattice, which we have previously applied to study polymers near a surface. The model retains the advantages of simple formulation and exact calculation of the conventional Bethe-like lattices. An antiferromagnetic Ising model is solved on the surface of this lattice to evaluate thermal properties such as free energy, energy density and entropy, from which we have successfully identified a first order order-disorder transition other than the spontaneous magnetization, and a secondary transition on the supercooled state indicated by the Kauzmann paradox.

cond-mat.stat-mech↗

Mechanical engineering of photon blockades in a cavity optomechanical system

We propose to mechanically control photon blockades (PB) in an optomechanical system with driving oscillators. We show that by tuning the mechanical driving parameters we achieve selective single-photon blockade (1PB) or two-photon blockade (2PB) as well as simultaneous 1PB and 2PB at the same frequency. This mechanical engineering of 1PB and 2PB can be understood from the anharmonic energy levels due to the modulation of the mechanical driving. In contrast to the optomechanical systems without any mechanical driving featuring PB only for specific optical detuning, our results can be useful for achieving novel photon sources with multi-frequency. Our work also opens up new route to mechanically engineer quantum states exhibiting highly nonclassical photon statistics.

quant-ph↗

Nonreciprocal Photon Blockade

We propose how to create and manipulate one-way nonclassical light via photon blockade in rotating nonlinear devices. We refer to this effect as nonreciprocal photon blockade (PB). Specifically, we show that in a spinning Kerr resonator, PB happens when the resonator is driven in one direction but not the other. This occurs because of the {Fizeau drag,} leading to a full split of the resonance frequencies of the countercirculating modes. Different types of purely quantum correlations, such as single- and two-photon blockades, can emerge in different directions in a well-controlled manner, and the transition from PB to photon-induced tunneling is revealed as well. Our work opens up a new route to achieve quantum nonreciprocal devices, which are crucial elements in chiral quantum technologies or topological photonics.

quant-ph↗

A Physical Review on Currency

A theoretical self-sustainable economic model is established based on the fundamental factors of production, consumption, reservation and reinvestment, where currency is set as a unconditional credit symbol serving as transaction equivalent and stock means. Principle properties of currency are explored in this ideal economic system. Physical analysis reveals some facts that were not addressed by traditional monetary theory, and several basic principles of ideal currency are concluded: 1. The saving-replacement is a more primary function of currency than the transaction equivalents; 2. The ideal efficiency of currency corresponds to the least practical value; 3. The contradiction between constant face value of currency and depreciable goods leads to intrinsic inflation.

econ.GN↗

Analytical Solution to the Transient Beam Loading Effects of the Superconducting Cavity

Transient beam loading effect is one of the key issues in any superconducting accelerators, which needs to be carefully investigated. The core problem in the analysis is to obtain the time evolution of cavity voltage under the transient beam loading. To simplify the problem, the second order ordinary differential equation describing the behavior of the cavity voltage is intuitively simplified to a first order one, with the aid of the two critical approximations lacking the proof for their validity. In this paper, the validity is examined mathematically in some specific cases, resulting in a criterion for the simplification. It's popular to solve the approximated equation for the cavity voltage numerically, while this paper shows that it can also be solved analytically under the step function approximation for the driven term. With the analytical solution to the cavity voltage, the transient reflected power from the cavity and the energy gain of the central particle in the bunch can also be calculated analytically. The validity of the step function approximation for the driven term is examined by direct evaluations. After that, the analytical results are compared with the numerical ones.

physics.acc-ph↗

Ising Spins on Randomly Multi-Branched Husimi Square Lattice: Thermodynamics and Phase Transition in Cross-dimensional Range

An inhomogeneous random recursive lattice was constructed from the multi-branched Husimi square lattice. The number of repeating units connected on one vertex was randomly set to be 2 or 3 with a quenched ratio $P_2$ or $P_3$ with $P_2+P_3=1$. The model was designed to describe complex thermodynamic systems with variable coordinating neighbors, e.g. the cross-dimensional range around the surface of a bulk materials. Classical ferromagnetic spin-1 Ising model was solved on the lattice to achieve an annealed solution via the local exact calculation technique. The model exhibits distinct spontaneous magnetization similar to the deterministic system, with however rigorous thermal fluctuations and significant singularities on the entropy behavior around the critical temperature, indicating a complex superheating and supercooling frustration in the cross-dimensional range induced by the stochasticity. The critical temperature was found to be exponentially correlated to the structural ratio $P$ with the coefficient fitted as 0.53187, while the ground state energy presents linear relation to $P$, implying a well-defined average property according to the structural ratio.

cond-mat.stat-mech↗

Striking Dispersion of Recrystallized Poly(ethylene glycol)-Poly(lactic acid) Solvent-Casting Blend

The solvent casted Poly(ethylene glycol) (PEG) and Poly(lactic acid) (PLA) blend was recrystallized by the thermal treatment of a heating and cooling cycle. The high PEG content blend (30\%wt) showed a striking dispersion behavior, that the materials rapidly dispersed and dissolved in the aqueous environment in a few hours. This phenomenon has not been reported by others, and was not observed in low PEG content samples of 5\%, 10\%, and 20\%, or quenched(amorphous) samples. We hypothesized the mechanism that the chain rearrangement during the thermal treatment leads to the phase separation. And with the phase separation in the recrystallized samples, the PEG potions rapidly dissolved in the aqueous environment, left out the small PLA spherulites being separated and dispersed in the solution. The same underlying reason can also be inferred from the degradation behaviors of other samples. Characterizations of DSC, XRD, and SEM have been done to validate our hypothesis.

cond-mat.mtrl-sci↗

Design Study on Medium beta SC Half-Wave Resonator at IMP

A superconducting half-wave resonator has been designed with the frequency of 325 MHz and beta of 0.51. Different geometry parameters and shapes of inner conductors (racetrack, ring-shape and elliptical-shape) were optimized to decrease the peak electromagnetic fields to obtain higher accelerating gradients and minimize the dissipated power on the cavity walls. To suppress the operation frequency shift caused by the helium pressure fluctuations and maximize the tuning ranges, the frequency shifts and mechanical properties were studied on the electric and magnetic areas separately. At the end, the helium vessel was also designed to keep the mechanical structure as robust as possible. The fabrication and test of the prototype will be completed in the beginning of 2016.

physics.acc-ph↗

Majorana zero modes in the hopping-modulated one-dimensional $p$-wave superconducting model

We investigate the one-dimensional $p$-wave superconducting model with periodically modulated hopping and show that under time-reversal symmetry, the number of the Majorana zero modes (MZMs) strongly depends on the modulation period. If the modulation period is odd, there can be at most one MZM. However if the period is even, the number of the MZMs can be zero, one and two. In addition, the MZMs will disappear as the chemical potential varies. We derive the condition for the existence of the MZMs and show that the topological properties in this model are dramatically different from the one with periodically modulated potential.

cond-mat.supr-con↗