• N D Chavda

Articles written in Pramana – Journal of Physics

• Shape transition of state density for bosonic systems

For a finite $m$ boson system, the ensemble-averaged state density has been computed with respect to the body interaction rank $k$. The shape of such a state density changes from Gaussian to semicircle as the body rank of the interaction increases. This state density is expressed as a linear superposition of Gaussian and semicircular states. The nearest-neighbour spacing distribution (NNSD), which is one of the most important spectral properties of a system, is studied. The NNSDs are rather independent of body rank $k$ and show a Wigner distribution throughout.

• Distribution of level spacing ratios using one- plus two-body random matrix ensembles

Probability distribution (𝑃(𝑟)) of the level spacing ratios has been introduced recently and is used to investigate many-body localization as well as to quantify the distance from integrability on finite size lattices. In this paper, we study the distribution of the ratio of consecutive level spacings using one-body plus two-body random matrix ensembles for finite interacting many-fermion and many-boson systems. 𝑃(𝑟) for these ensembles move steadily from the Poisson to the Gaussian orthogonal ensemble (GOE) form as the two-body interaction strength 𝜆 is varied. Other related quantities are also used in the analysis to obtain critical strength 𝜆c for the transition. The 𝜆c values deduced using the 𝑃(𝑟) analysis are in good agreement with the results obtained using the nearest neighbour spacing distribution (NNSD) analysis.

• # Pramana – Journal of Physics

Volume 96, 2022
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Posted on July 25, 2019

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