---
abstract: 'We explore Casimir effect on an interacting Bose-Einstein condensate (BEC) inside a cylindrical tube. The Casimir force for the confined BEC comprises of (i) a mean-field part arising from the spatial inhomogeneity of the condensate order parameter, and (ii) a quantum fluctuation part arising from the confinement of Bogoliubov excitations in the condensate. Our analytical result predicts Casimir force on a cylindrical shallow of $^4$He well below the $\lambda$-point, and can be tested experimentally.'
author:
- Shyamal Biswas$^1$
- Saugata Bhattacharyya$^2$
- Amit Agarwal$^3$
title: 'Casimir effect for a Bose-Einstein condensate inside a cylindrical tube'
---

Introduction {#Sec1}
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Casimir (like) or fluctuation induced force arises due to confinement of fluctuations, either classical or quantum, and depends upon the confining geometry of the system [@Casimir; @Krech; @Golestanian; @Gambassi]. Casimir effect due to the confinement of classical (critical) fluctuations is found to be stronger than the corresponding effect due to the confinement of the quantum (vacuum) fluctuations [@Mohideen; @Chan2; @Hertlein]. Systems with different geometry of the confining plates, eg. sinusoidally corrugated geometry, eccentric-cylindrical geometry, grating geometry, parabolic geometry, concentric-cylindrical geometry, etc, have also been studied both experimentally and theoretically, in the context of the quantum Casimir force [@Emig; @Chen; 