Delayed entanglement echo for individual control of a large number of nuclear spins

Abstract

Methods to selectively detect and manipulate nuclear spins by single electrons of solid-state defects play a central role for quantum information processing and nanoscale nuclear magnetic resonance (NMR). However, with standard techniques, no more than eight nuclear spins have been resolved by a single defect centre. Here we develop a method that improves significantly the ability to detect, address and manipulate nuclear spins unambiguously and individually in a broad frequency band by using a nitrogen-vacancy (NV) centre as model system. On the basis of delayed entanglement control, a technique combining microwave and radio frequency fields, our method allows to selectively perform robust high-fidelity entangling gates between hardly resolved nuclear spins and the NV electron. Long-lived qubit memories can be naturally incorporated to our method for improved performance. The application of our ideas will increase the number of useful register qubits accessible to a defect centre and improve the signal of nanoscale NMR.

A quantum spectrum analyzer enhanced by a nuclear spin memory

“…Active manipulation of both nuclei during the waiting time could, for example, be used to individually address a large number of weakly coupled 13 C spins. 42 Advanced NMR concepts, such as multi-dimensional spectroscopy 22,43 or spectral editing could be used to study interactions between nuclei. 44 These concepts will likely require compressed sensing methods 11,45 and efficient NV readout 23,46 to accelerate data collection.…”

Arbitrary nuclear-spin gates in diamond mediated by a nitrogen-vacancy-center electron spin

“…With the dynamical decoupling techniques in [18][19][20]33], one can achieve highly selective entangling quantum gates of the form…”

“…], where each of the previous two-qubit gates can be realised with [18][19][20]33] plus additional single-qubit gates on the electron spin. Note also that a selective iSWAP gate (with iSWAP e, j n = exp [i…”

“…Note that σ z = |m s = ±1 m s ± 1| − |m s = 0 m s = 0| corresponds to an effective electronic spin-1 2 operator [7,8], while I x , I y are nuclear spin operators with I = 1 2 . In addition, in [33] it is shown how the judicious application of a delay window achieves an interaction of the kind σ z I z . Furthermore, these techniques can incorporate a decoupling rf field [19,20,33] to combine electron-nuclear entangling gate generation with a suppression of the internuclear decoupling.…”

“…In addition, in [33] it is shown how the judicious application of a delay window achieves an interaction of the kind σ z I z . Furthermore, these techniques can incorporate a decoupling rf field [19,20,33] to combine electron-nuclear entangling gate generation with a suppression of the internuclear decoupling.…”