does an external magnetic field destroy quantum coherence

Here we study the possibility of simulating open quantum systems through an extension of the idea of dynamical decoupling and apply it to NV centers. NV centers have been proposed to simulate various quantum systems and realized in experiment, for example Helium Hydride Cation 51 and directly measuring topological quantum number 53.

Moreover, an extension of dynamical decoupling is possible for universal quantum computation 46, 47, and other applications 48, 49.Īs one of the most promising platform of quantum computation and quantum simulation 50, 51, 52, 53, Nitrogen-Vacancy(NV) center in diamond can be manipulated in room temperature with a long coherence time. Experimental implementations of dynamical decoupling indicate that such approach is widely applicable to various experimental platforms 38, 39, 40, 41, 42, 43, 44, 45. An important approach to tackle the decoherence problem, called dynamical decoupling 30, 31, 32, 33, 34, 35, 36, has been developed to significantly eliminate the system-environment interactions 37, through a sequence of external pulses applied to the system. Similarly, analog quantum simulators of open quantum system has been theoretically proposed 28 and experimentally investigated 29. In the literature, digital approaches of open-system quantum simulation 24, 25, 26, 27 have been theoretically studied and experimentally demonstrated. Furthermore, it is important to understand how a quantum simulator can simulate open quantum systems 20, which is also intractable since the large number of degree of environment but of fundamental importance for understanding many physical phenomena in, for example, quantum optics 21, quantum measurement 22, and biological systems 23. In practice, a quantum simulator is necessarily an open quantum system, where the underlying system-environment interaction 20 plays the main role in determining the performance of a quantum simulator. The main challenge of constructing a practical quantum simulator is to reduce the influence of environmental decoherence, a universal problem for all tasks in quantum information processing including quantum communication 19. The other kind of quantum simulators are called analog quantum simulators 12, 13, 14, 15, 16, where the Hamiltonian of the simulated quantum system is directly engineered in a dedicated quantum device, for example, trapped ions 14, 17 and optical lattices 18. The first type, called digital quantum simulator 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, makes use of a general-purpose quantum computer, where quantum states are encoded with qubits and the dynamical evolution is programmed in a quantum circuit. Generally, there are two types of quantum simulators.

Our numerical simulations, based on experimentally-feasible parameters, indicate that decoherence of Nitrogen-Vacancy centers can be controlled externally to a very large extend.Ī quantum simulator 1, 2, 3, 4, 5 is potentially a powerful tool for solving many-body problems that are not tractable by classical methods. Motivated by simulating quantum open systems with Nitrogen-Vacancy centers, which has become an increasingly important platform for quantum information processing tasks, we developed a new set of steering pulse sequences for controlling various coherence times of Nitrogen-Vacancy centers our method is based on a hybrid approach that exploits ingredients in both digital and analog quantum simulations to dynamically couple or decouple the system with the physical environment. The key to the success in simulating those open quantum systems is therefore the ability of controlling decoherence, instead of eliminating it. Although decoherence is detrimental for most of the tasks in quantum information processing, a substantial degree of decoherence is crucial for boosting the efficiency of quantum processes, for example, in quantum biology and other open systems. Quantum mechanical systems lose coherence through interacting with external environments-a process known as decoherence.

Does an external magnetic field destroy quantum coherence