Optimized nonadiabatic holonomic quantum computation based on Förster resonance in Rydberg atoms

In this paper,we propose a scheme for implementing the nonadiabatic holonomic quantum computation(NHQC+)of two Rydberg atoms by using invariant-based reverse engineering(IBRE).The scheme is based on Förster resonance induced by strong dipole-dipole interaction between two Rydberg atoms,which provides a selective coupling mechanism to simply the dynamics of system.Moreover,for improving the fidelity of the scheme,the optimal control method is introduced to enhance the gate robustness against systematic errors.Numerical simulations show the scheme is robust against the random noise in control fields,the deviation of dipole-dipole interaction,the Förster defect,and the spontaneous emission of atoms.Therefore,the scheme may provide some useful perspectives for the realization of quantum computation with Rydberg atoms.

Fast holonomic quantum computation based on solid-state spins with all-optical control

Holonomic quantum computation is a quantum computation strategy that promises some built-in noise-resilience features. Here,we propose a scheme for nonadiabatic holonomic quantum computation with nitrogen-vacancy center electron spins, which are characterized by fast quantum gates and long qubit coherence times. By varying the detuning, amplitudes, and phase difference of lasers applied to a nitrogen-vacancy center, one can directly realize an arbitrary single-qubit holonomic gate on the spin.Meanwhile, with the help of cavity-assisted interactions, a nontrivial two-qubit holonomic quantum gate can also be induced. The distinct merit of this scheme is that all the quantum gates are obtained via an all-optical geometric manipulation of the solid-state spins. Therefore, our scheme opens the possibility for robust quantum computation using solid-state spins in an all-optical way.

Nonadiabatic holonomic quantum computation based on nitrogen-vacancy centers

Because of quantum superposition, quantum computation can solve many problems, such as factoring large integers [ 1 ] and searching unsorted databases [2,3], much faster than clas- sical computation. To realize practical quantum computation and then gain the desired advantages, a universal set of quantum gates with sufficiently high fidelities are needed. However, various inevitable errors reduce the gate fidelities and finally collapse the computation results, which makes the realizations of quantum computation very challenging.

Experimental realization of single-shot nonadiabatic holonomic gates in nuclear spins

Nonadiabatic holonomic quantum computation has received increasing attention due to its robustness against control errors. However, all the previous schemes have to use at least two sequentially implemented gates to realize a general one-qubit gate. Based on two recent reports, we construct two Hamiltonians and experimentally realized nonadiabatic holonomic gates by a single-shot implementation in a two-qubit nuclear magnetic resonance （NMR） system. Two noncommuting one-qubit holonomic gates, rotating along .~ and ~ axes respectively, are implemented by evolving a work qubit and an ancillary qubit nonadiabatically following a quantum circuit designed. Using a sequence compiler developed for NMR quantum information processor, we optimize the whole pulse sequence, minimizing the total error of the implementation. Finally, all the nonadiabatic holonomic gates reach high unattenuated experimental fidelities over 98%.

Quantum control of bosonic modes with superconducting circuits

Bosonic modes have wide applications in various quantum technologies,such as optical photons for quantum communication,magnons in spin ensembles for quantum information storage and mechanical modes for reversible microwave-to-optical quantum transduction.There is emerging interest in utilizing bosonic modes for quantum information processing,with circuit quantum electrodynamics(circuit QED)as one of the leading architectures.Quantum information can be encoded into subspaces of a bosonic superconducting cavity mode with long coherence time.However,standard Gaussian operations(e.g.,beam splitting and two-mode squeezing)are insufficient for universal quantum computing.The major challenge is to introduce additional nonlinear control beyond Gaussian operations without adding significant bosonic loss or decoherence.Here we review recent advances in universal control of a single bosonic code with superconducting circuits,including unitary control,quantum feedback control,drivendissipative control and holonomic dissipative control.Various approaches to entangling different bosonic modes are also discussed.