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C. Zou

Publications and source records attributed to C. Zou.

7 recordsLinked to original sources

Variational Scarring in Graphene Quantum Dots

A quantum eigenstate of a classically chaotic system is referred as scarred by an unstable periodic orbit if its probability density is concentrated in the vicinity of that orbit. Recently, a new class of scarring - variational scarring - was discovered in numerical studies of disordered quantum dots, arising from near-degeneracies in the quantum spectrum associated with classical resonances of the unperturbed system. Despite the increasing body of theoretical evidence on variational scarring, its experimental observation has remained out of reach. Motivated by this dearth, we argue and demonstrate that variational scarring can occur in an elliptical quantum dot fabricated on monolayer graphene, and locally perturbed by a nanotip. Then, we further show that the fingerprint of these variational scars can potentially be detected via scanning tunneling microscopy, thus offering an attractive experimental pathway for the first validation of this puzzling quantum-chaotic phenomenon.

cond-mat.mes-hall

Probing polarization response of monolayer cell cultures with photon entanglement

This study addresses the critical need for high signal-to-noise ratio in optical detection methods for biological sample discrimination under low-photon-flux conditions to ensure accuracy without compromising sample integrity. We explore polarization-based probing, which often excels over intensity modulation when assessing a specimen's morphology. Leveraging non-classical light sources, our approach capitalizes on sub-Poissonian photon statistics and quantum correlation-based measurements. We present a novel, highly sensitive method for probing single-layer cell cultures using entangled photon pairs. Our approach demonstrates capability in monolayer cell analysis, distinguishing between two types of monolayer cells and their host medium. The experimental results highlight our method's sensitivity, showcasing its potential for biological sample detection using quantum techniques, and paving the way for advanced diagnostic methodologies.

physics.optics

Wafer-size VO2 film prepared by water-vapor oxidant

The growth of wafer-scale and uniform monoclinic VO2 film was a challenge if considering the multivalent vanadium atom and the various phase structures of VO2 compound. Directly oxidizing metallic vanadium film in oxygen gas seemed to be an easy way, while the oxidation parameters were extremely sensitive due to the critical preparation window. Here we proposed a facile thermal oxidation by water-vapor to produce wafer-scale VO2 films with high quality. Results indicated that by using the water-vapor oxidant, the temperature window for VO2 growth was greatly broadened. In addition, the obtained wafer-size VO2 film showed very uniform surface and sharp resistance change. The chemical reaction routes with water-vapor were calculated, which favored the VO2 film growth. Our results not only demonstrated that the water-vapor could be used as a modest oxidizing agent, but also showed the unique advantage for large size VO2 film preparation.

cond-mat.mtrl-sci

Quotient Complexity of Closed Languages

A language L is prefix-closed if, whenever a word w is in L, then every prefix of w is also in L. We define suffix-, factor-, and subword-closed languages in the same way, where by subword we mean subsequence. We study the quotient complexity (usually called state complexity) of operations on prefix-, suffix-, factor-, and subword-closed languages. We find tight upper bounds on the complexity of the prefix-, suffix-, factor-, and subword-closure of arbitrary languages, and on the complexity of boolean operations, concatenation, star and reversal in each of the four classes of closed languages. We show that repeated application of positive closure and complement to a closed language results in at most four distinct languages, while Kleene closure and complement gives at most eight languages.

cs.FL

Directed flow of antiprotons in Au+Au collisions at AGS

Directed flow of antiprotons is studied in Au+Au collisions at a beam momentum of 11.5A GeV/c. It is shown that antiproton directed flow is anti-correlated to proton flow. The measured transverse momentum dependence of the antiproton flow is compared with predictions of the RQMD event generator.

nucl-ex

Directed Flow of Light Nuclei in Au+Au Collisions at AGS Energies

Directed flow of deuterons, tritons, $^3$He, and $^4$He is studied in Au+Au collisions at a beam momentum of about 10.8 $A$ GeV/c. Flow of all particles is analyzed as a function of transverse momentum for different centralities of the collision. The directed flow signal, $v_1(p_t)$, is found to increase with particle mass. This mass dependence is strongest in the projectile rapidity region.

nucl-ex

Two-pion correlations in Au+Au collisions at 10.8 GeV/c per nucleon

Two-particle correlation functions for positive and negative pions have been measured in Au+Au collisions at 10.8~GeV/c per nucleon. The data were analyzed using one- and three-dimensional correlation functions. From the results of the three-dimensional fit the phase space density of pions was calculated. It is consistent with local thermal equilibrium.

physics.acc-ph