arXiv subjects

Zhi-Zhan Xu

Publications and source records attributed to Zhi-Zhan Xu.

4 recordsLinked to original sources

arXiv2016

Probing quantum grav ity effects with ion trap

The existence of minimal length scale has motivated the proposal of generalized uncertainty principle, which provides a potential routine to probe quantum gravitational effects in low-energy quantum mechanics experiment. Hitherto, the tabletop experiment of testing deviations from ordinary quantum mechanics are mostly based on microscopic objects. However, the feasibility of these studies are challenged by the recent study of spacetime quantization for composite macroscopic body. In this paper, we propose a scheme to probe quantum gravity effects by revealing the deviations from predictions of Heisenberg uncertainty principle. Our scheme focus on manipulating the interaction sequences between external laser fields and a single trapped ion to seek evidence of spacetime quantization, therefore reduce the complicity induced by large bodies to some extent. The relevant study for microscopic particles is crucial considering the lack of satisfactory theories regarding basic properties for multi-particles in the framework of quantum gravity. Meanwhile, we are managed to set a new upper limit for deformation parameter.

quant-ph↗

arXiv2015

The origin of the Redshift Spikes in the reflection spectrum of a Few-cycle Pulse in a Dense Medium

We give a detailed description about the reflected spectrum of a few-cycle pulse propagating through a resonant dense medium. An unexpected low-frequency spike appeared in the red edge of the spectrum. To figure out the origin of this redshift spike, we analysis the mechanisms responsible for the redshift of the reflected field. So far, the redshift has not been well studied for few-cycle pulses except a brief explanation made by the previous study [Kaloshan et al., Phys. Rev. Lett. 83 544 (1999).], which attributed the origin of the redshift to the so-called intrapulse four-wave mixing. However, we demonstrate numerically that the redshift consists of two separated spikes is actually produced by the Doppler effect of backpropagation waves, which is an analogue effect of dynamic nonlinear optical skin effect. Our study elucidates the underlying physics of the dynamic nonlinear optical effects responsible for the redshift spikes. Moreover, the dependency of the their frequency on the laser and medium parameters, such as medium density and input pulse area are also discussed.

physics.optics↗

arXiv2014

Squeezing effect induced by minimal length uncertainty

In this work, the dynamics of the deformed one-dimensional harmonic oscillator with minimal length uncertainty is examined and the analytical solutions for time evolution of position and momentum operators are presented in which the rough approximation that neglects the higher order terms in BakerHausdor lemma is avoided. Based on these analytical solutions the uncertainties for position and momentum operators are calculated in a coherent state, and an unexpected squeezing effect in both coordinate and momentum directions is found in comparison with ordinary harmonic oscillator. Obviously such a squeezing effect is induced by the minimal length uncertainty (gravitational effects). Our results are applied to the electrons trapped in strong magnetic fields to examine the degree of the existing squeezing effect in a real system, which shows the squeezing degree induced by minimal length uncertainty is very small.

quant-ph↗

arXiv2003

Beam Splitter Entangler for Light Fields

We propose an experimentally feasible scheme to generate various types of entangled states of light fields by using beam splitters and single-photon detectors. Two light fields are incident on two beam splitters and are split into strong and weak output modes respectively. A conditional joint measurement on both weak output modes may result in an entanglement between the two strong output modes. The conditions for the maximal entanglement are discussed based on the concurrence. Several specific examples are also examined.

quant-ph↗