218 research outputs found
Gravitational and Relativistic Deflection of X-Ray Superradiance
Exploring Einstein's theories of relativity in quantum systems, for example
by using atomic clocks at high speeds can deepen our knowledge in physics.
However, many challenges still remain on finding novel methods for detecting
effects of gravity and of special relativity and their roles in light-matter
interaction. Here we introduce a scheme of x-ray quantum optics that allows for
a millimeter scale investigation of the relativistic redshift by directly
probing a fixed nuclear crystal in Earth's gravitational field with x-rays.
Alternatively, a compact rotating crystal can be used to force interacting
x-rays to experience inhomogeneous clock tick rates in a crystal. We find that
an association of gravitational or special-relativistic time dilation with
quantum interference will be manifested by deflections of x-ray photons. Our
protocol suggests a new and feasible tabletop solution for probing effects of
gravity and special relativity in the quantum world.Comment: 17 pages, 4 figures, 1 table and Supplemental Material
Optomechanically induced transparency of x-rays via optical control
The search for new control methods over light-matter interactions is one of
the engines that advances fundamental physics and applied science alike. A
specific class of light-matter interaction interfaces are setups coupling
photons of distinct frequencies via matter. Such devices, nontrivial in design,
could be endowed with multifunctional tasking. Here we envisage for the first
time an optomechanical system that bridges optical and robust, high-frequency
x-ray photons, which are otherwise notoriously difficult to control. The
x-ray-optical system comprises of an optomechanical cavity and a movable
microlever interacting with an optical laser and with x-rays via resonant
nuclear scattering. We show that optomechanically induced transparency of a
broad range of photons (10 eV-100 keV) is achievable in this setup, allowing to
tune nuclear x-ray absorption spectra via optomechanical control. This paves
ways for metrology applications, e.g., the detection of the Thorium
clock transition, and an unprecedentedly precise control of x-rays using
optical photons.Comment: 2 figures, supplementary material available with the file
Generation of short hard X-ray pulses of tailored duration using a M\"ossbauer source
We theoretically investigate a scheme for generations of single hard X-ray
pulses of controllable duration in the range of 1 ns - 100 ns from a
radioactive M\"ossbauer source. The scheme uses a magnetically perturbed
FeBO crystal illuminated with recoilless 14.4 keV photons from a
radioisotope Co nuclide. Such compact X-ray source is useful for the
extension of quantum optics to 10 keV energy scale which has been spotlighted
in recent years. So far, experimental achievements are mostly performed in
synchrotron radiation facilities. However, tabletop and portable hard X-ray
sources are still limited for time-resolved measurements and for implementing
coherent controls over nuclear quantum optics systems. The availability of
compact hard X-ray sources may become the engine to apply schemes of quantum
information down to the subatomic scale. We demonstrate that the present method
is versatile and provides an economic solution utilizing a M\"ossbauer source
to perform time-resolved nuclear scattering, to produce suitable pulses for
photon storage and to flexibly generate X-ray single-photon entanglement.Comment: 8 pages, 6 figure
Field control of single x-ray photons in nuclear forward scattering
Means to coherently control single x-ray photons in resonant scattering of
light off nuclei by electric or magnetic fields are investigated theoretically.
In order to derive the time response in nuclear forward scattering, we adapt
the Maxwell-Bloch equations known from quantum optics to describe the resonant
light pulse propagation through a nuclear medium. Two types of time-dependent
perturbations of nuclear forward scattering are considered for coherent control
of the resonantly scattered x-ray quanta. First, the simultaneous coherent
propagation of two pulses through the nuclear sample is addressed. We find that
the signal of a weak pulse can be enhanced or suppressed by a stronger pulse
simultaneously propagating through the sample in counter-propagating geometry.
Second, the effect of a time-dependent hyperfine splitting is investigated and
we put forward a scheme that allows parts of the spectrum to be shifted forward
in time. This is the inverse effect of coherent photon storage and may become a
valuable technique if single x-ray photon wavepackets are to become the
information carriers in future photonic circuits.Comment: 21 pages, 10 figures, v2 minor modifications in text to match the
published version, results unchange
A three-beam setup for coherently controlling nuclear state population
The controlled transfer of nuclear state population using two x-ray laser
pulses is investigated theoretically. The laser pulses drive two nuclear
transitions in a nuclear three-level system facilitating coherent population
transfer via the quantum optics technique of stimulated Raman adiabatic
passage. To overcome present limitations of the x-ray laser frequency, we
envisage accelerated nuclei interacting with two copropagating or crossed x-ray
laser pulses in a three-beam setup. We present a systematic study of this setup
providing both pulse temporal sequence and laser pulse intensity for optimized
control of the nuclear state population. The tolerance for geometrical
parameters such as laser beam divergence of the three-beam setup as well as for
the velocity spread of the nuclear beam are studied and a two-photon resonance
condition to account for experimental uncertainties is deduced. This additional
condition gives a less strict requirement for the experimental implementation
of the three-beam setup. Present experimental state of the art and future
prospects are discussed.Comment: 13 pages, 9 figures and 4 tables. arXiv admin note: substantial text
overlap with arXiv:1011.442
All-Electromagnetic Control of Broadband Quantum Excitations Using Gradient Photon Echoes
A broadband quantum echo effect in a three level -type system
interacting with two laser fields is investigated theoretically. Inspired by
the emerging field of nuclear quantum optics which typically deals with very
narrow resonances, we consider broadband probe pulses that couple to the system
in the presence of an inhomogeneous control field. We show that such a setup
provides an all-electromagnetic-field solution to implement high bandwidth
photon echoes, which are easy to control, store and shape on a short time scale
and therefore may speed up future photonic information processing. The time
compression of the echo signal and possible applications for quantum memories
are discussed.Comment: 5 pages, 4 figure
Coherence-enhanced optical determination of the Th isomeric transition
The impact of coherent light propagation on the excitation and fluorescence
of thorium nuclei in a crystal lattice environment is investigated
theoretically. We find that in the forward direction the fluorescence signal
exhibits characteristic intensity modulations dominated by an orders of
magnitude faster, sped-up initial decay signal. This feature can be exploited
for the optical determination of the isomeric transition energy. In order to
obtain a unmistakable signature of the isomeric nuclear fluorescence, we put
forward a novel scheme for the direct measurement of the transition energy via
electromagnetically modified nuclear forward scattering involving two fields
that couple three nuclear states.Comment: 11 pages, 2 figures; v2 updated to the published version (minor
changed in text
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