Dynamically Decoupled $^{13}$C Spins in Hyperpolarized Nanodiamond

The spin-spin relaxation time, T$_2$, which determines how long a quantum state remains coherent, is an important factor for many applications ranging from MRI to quantum computing. A common technique used in quantum information technology to extend the T$_2$, involves averaging out certain noise spectra via dynamical decoupling sequences. Depending on the nature of the noise in the system, specific sequences, such as CPMG, UDD or KDD, can be tailored to optimize T$_2$. Here we combine hyperpolarization techniques and dynamical decoupling sequences to extend the T$_2$ of $^{13}$C nuclear spins in nanodiamond by three orders of magnitude.