Single-electron spin logical gates

Masanori Ohya, Igor Vasil'evich Volovich, Noboru Watanabe

Amit Ranjan Trivedi, Supriyo Bandyopadhyay

The Toffoli–Fredkin (TF) gate is a universal reversible logic gate capable of performing logic operations without dissipating energy. Here, we show that a linear array of three quantum dots, each hosting a single electron, can realize the TF gate, if we encode logic bits in the spin polarization of the electrons and allow nearest neighbor exchange coupling. The dynamics of the TF gate is realized by selectively driving spin resonances in the coupled spin system with an ac magnetic field. The conditions for gate operation are established, and an estimate of the switching speed and gate error are provided.

Fedor Jelezko, T. Gaebel, I. Popa +3 more

A quantum logical NOT and a conditional two-qubit gate (CROT), are implemented with single spins in a solid. As quantum bits a single electron spin and a single 13C nuclear spin of a single nitrogen vacancy defect center in diamond are used. The quantum state of the electron spin can be read out optically. Owing to long decoherence and relaxation times the systems meets the requirements of hardware for quantum computation. Density matrix tomography of the CROT gate shows that the achieved performance of the two bit conditional quantum gate is promising. The gate fidelity achieved in our experiments is up to 0.9, good enough to be used in quantum algorithms. Further on, the system may allow for solid-state room temperature quantum computation

Giacomo Ciaramicoli, Irene Marzoli, Paolo Tombesi

We show how a single trapped electron offers the opportunity to realize universal quantum logic gates within the present experimental possibilities. As an example, we propose to implement the Deutsch algorithm by using the quantized cyclotron motion and the electron spin as qubits.

M. Yaghouti, Mehdi Farzanehpour, Mohammad Javad Sharifi