## Abstract

We measure the dependence of the interparticle force F on the distance R between two colloidal particles with hyperbolic hedgehog defects in a nematic liquid crystal using optical tweezers. The particle-defect pair can be regarded as an elastic "dipole" in the electrostatic analogy. In a parallel configuration, where the dipole vectors are parallel with each other, F is attractive and proportional to R-4. However, F becomes repulsive at small R due to the existence of a defect between the particles. In an antiparallel configuration, where the particles directly face each other, F is repulsive over the whole range of R and proportional to R-3.6. In another antiparallel configuration, where two hyperbolic hedgehog defects directly face each other, F is proportional to R-3.6 and F at small R turns out to be attractive upon tilting the dipoles. Furthermore, we yield the force between particles connected by a stringlike defect called a bubblegum defect.

Original language | English |
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Article number | 020703 |

Journal | Physical Review E - Statistical, Nonlinear, and Soft Matter Physics |

Volume | 77 |

Issue number | 2 |

DOIs | |

Publication status | Published - Feb 25 2008 |

## All Science Journal Classification (ASJC) codes

- Statistical and Nonlinear Physics
- Statistics and Probability
- Condensed Matter Physics