# Bubble-bound state of triple-stranded DNA: Efimov Physics in DNA with repulsion

## TL;DR

This paper demonstrates the existence of a thermodynamic phase in three-stranded DNA involving bubble states and mixed phases, using exact renormalization group methods across different dimensions, revealing novel Efimov-like phenomena.

## Contribution

It introduces a new thermodynamic phase in three-stranded DNA with bubble states and mixed phases, analyzed through exact RG methods in various dimensions, highlighting Efimov physics in DNA.

## Key findings

- Existence of a bubble-bound phase in three-stranded DNA for large dimensions.
- Stability of the phase in fractal structures with repulsive interactions.
- Identification of Efimov-like phenomena in DNA strand interactions.

## Abstract

The presence of a thermodynamic phase of a three-stranded DNA, namely, a mixed phase of bubbles of two bound strands and a single one, is established for large dimensions ($d\geq 5$) by using exact real space renormalization group (RG) transformations and exact computations of specific heat for finite length chains. Similar exact computations for the fractal Sierpinski gasket of dimension $d<2$ establish the stability of the phase in presence of repulsive three chain interaction. In contrast to the Efimov DNA, where three strands are bound though no two are bound, the mixed phase appears on the bound side of the two chain melting temperature. Both the Efimov-DNA and the mixed phase are formed due to strand exchange mechanism.