Microwave quantum logic gates for trapped ions

Abstract

Control over physical systems at the quantum level is a goal shared by scientists in fields as diverse as metrology, information processing, simulation and chemistry. For trapped atomic ions, the quantized motional and internal degrees of freedom can be coherently manipulated with laser light.1, 2 Similar control is difficult to achieve with radio frequency or microwave radiation because the essential coupling between internal degrees of freedom and motion requires significant field changes over the extent of the atoms' motion. 2, 3 The field gradients are negligible at these frequencies for freely propagating fields; however, stronger gradients can be generated in the near-field of microwave currents in structures smaller than the free-space wavelength. 4,5 In the experiments reported here, we coherently manipulate the internal quantum states of the ions on time scales of 20 ns. We also generate entanglement between the internal degrees of freedom of two atoms with a gate operation 4, 6-8 suitable for general quantum computation. 9 We implement both operations through the magnetic fields from 1 arXiv:1104.3573v3 [quant-ph]

Reversing hydride-ion formation in quantum-information experiments withBe+

“…Jt, 33.80.Gj, 34.50.Lf, Crystals of laser-cooled atomic ions form the basis of many experimental realizations of quantum logic gates [1][2][3] and simulations of quantum many-body physics [4][5][6]. In room-temperature vacuum systems, collisions with neutral background gas molecules limit quantum coherences and quantum logic operations [7].…”

Towards Quantum Logic Inspired Cooling and Detection for Single (Anti-)Protons

“…As the wavelength of the spin-flip transition for the (anti-)proton is rather long compared to the spatial extent of its motion, special measures need to be taken in order to be able to jointly (de-)excite motional and internal degrees of freedom of the particle. Similar protocols have been implemented with atomic ions in the context of quantum logic operations using microwave radiation [16,17] and have been adapted for the cylindrical Penning trap geometry of the present project.…”

Measuring and manipulating the temperature of cold molecules trapped on a chip

“…A promising tool for the control and manipulation of cold molecules is the molecule chip [12][13][14], the molecular analog of the atom chip [15][16][17][18] or ion chip [19,20]. Using the molecule chip, we have recently demonstrated the integrated on-chip time-resolved spatial imaging of cold molecules in a manner that is both quantum state selective and generally applicable [14].…”