Logical operations with single x-ray photons via dynamically-controlled nuclear resonances

Abstract

Photonic qubits lie at the heart of quantum information technology, often encoding information in their polarization state. So far, only low-frequency optical and infrared photons have been employed as flying qubits, as the resources that are at present easiest to control. With their essentially different way of interacting with matter, x-ray qubits would bear however relevant advantages: they are extremely robust, penetrate deep through materials, and can be focused down to few-nm waveguides, allowing unprecedented miniaturization. Also, x-rays are resonant to nuclear transitions, which are very well isolated from the environment and present long coherence times. Here, we show theoretically that x-ray polarization qubits can be dynamically controlled by nuclear Mössbauer resonances. The control knob is played by nuclear hyperfine magnetic fields, that allow via fast rotations precise processing of single x-ray quanta polarization. With such rotations, single-qubit and binary logical operations such as a destructive C-NOT gate can be implemented.

Creation of single-photon entangled states around rotating black holes

“…The detection and measurement of entangled states are very common these days in optical quantum information processes. Precise setups to measure all four Bell states of single-photons, in polarization and OAM modes, have been reported [20], [22],.…”

Green's-function formalism for resonant interaction of x rays with nuclei in structured media

“…These developments provide potential applications in the fields of metrology, material science, quantum information, biology, and chemistry. From the theoretical side, several works have addressed promising control schemes for stopping and manipulating x-ray quanta [15][16][17][18][19][20][21].…”

The theory of direct laser excitation of nuclear transitions

“…When achieved, potential applications in various physical fields open up. These include the development of a highly stable source of light for metrology [1], the development of a nuclear optical clock [2,3], a nuclear γ-ray laser [4,5] and a nuclear qubit for quantum computing [6]. Further, it will advance the field of experimental nuclear quantum optics [7][8][9].…”