Quantum Simulation of Bound and Resonant Doubly-Bottom Tetraquark

TL;DR

The paper addresses the existence of bound and resonant doubly-bottom tetraquarks within a QCD-inspired chiral quark model and demonstrates a quantum-simulation approach to study them. It maps the four-quark problem onto a 16-qubit register encoding color, spin, and spatial degrees of freedom, and uses a variational quantum eigensolver within coupled meson-meson and diquark-antidiquark bases to identify low-lying $S$-wave states. The key findings are two deeply bound isoscalar states in $I(J^{P})=0(1^{+})$ with masses around $10545$ MeV and $10563$ MeV and binding energies near $-59$ and $-40$ MeV, respectively, with resonances and hidden-color effects providing nontrivial contributions; results are consistent with classical chiral quark-model predictions. Overall, the work establishes quantum simulation as a viable route to explore exotic multiquark spectroscopy and real-time color dynamics beyond the reach of conventional methods.

Abstract

We present the first quantum-simulation study of bound and resonant doubly-bottom tetraquark states within a QCD-inspired chiral quark model. An effective four-quark Hamiltonian is mapped onto a 16-qubit register, encoding color, spin, and spatial degrees of freedom, and incorporating both meson-meson and diquark-antidiquark configurations with complete color bases. Using a variational quantum eigensolver, we identify bound and resonance states in the low-lying $S$-wave sector. Deeply bound states are found exclusively in the isoscalar $I(J^{P})=0(1^{+})$ channel, dominated by color-singlet meson-meson components with non-negligible hidden-color contributions. The resulting masses and binding energies are consistent with classical chiral quark model predictions, establishing quantum simulation as a viable framework for studying exotic multiquark states beyond the reach of conventional methods.

Figures (2)

• Figure 1: Schematic for (a) meson-meson and (b) diquark-antidiquark configurations for double-bottom tetraquark $(Q=b$ and $q=u,d)$.
• Figure 2: The 16 qubit quantum circuit for MM configuration of double-bottom tetraquark. The first cell enforces color singlet-singlet projection, while the second cell projects spin $S=0$. Last four cells assign spatial projection.