Researchers describe a theoretical mechanism that may ensure high-fidelity entanglement of photons, and thus could be used to construct a practical quantum repeater. The communication rate is shown to be a function of the maximum distance between any two adjacent quantum repeaters, rather than of the entire length of the network.
By using bright pulses of light to ‘blind’ the avalanche photodiode detectors used in quantum cryptography equipment, scientists in Europe have shown that it is possible to tracelessly steal the secret encryption key generated by such systems and thus compromise their security.
Researchers demonstrate random-number generation by exploiting the intrinsic randomness of vacuum states. The approach may lead to reliable and high-speed quantum random-number generators for applications ranging from gambling to cryptography.
Coherent Rabi flopping and coherent pulse reshaping are directly observed in an operating quantum cascade laser. The findings indicate the potential for coherent effects to be exploited in mode locking, and may stimulate new approaches for generating short pulses in quantum cascade lasers.
An optical cavity coupled to a micrometre-sized mechanical resonator offers the opportunity to see quantum effects in relatively large structures. It is now shown that a variety of coupling mechanisms enable investigation of these fascinating systems in a number of different ways.
At absolute zero temperature, exotic phases of matter can be found near a quantum critical point. If geometric frustration is also present, as happens in columbite, the extra quantum fluctuations lead to five distinct states of matter.
The properties of electric conductors change markedly once quantum phenomena become relevant. So far, work on quantum coherent electron transport has largely focused on static properties, but new theoretical work now looks at such phenomena in the regime of fast alternating currents.
Owing to incomplete data, it is difficult to establish tropical cyclone behaviour over long timescales. However, by considering the total released energy of individual cyclones, it is possible to establish changes of cyclone energy and their connection to climate change.
Although solar flares are the most energetic events that occur in our Solar System, very little is known about their contribution to the total energy the Earth receives from the Sun. The identification of a measurable signal from a moderate-sized solar flare in total solar irradiance data suggests their impact on the variability of the Sun’s output could be larger than expected.
