Don’t be sad! Because God sends hope in the most desperate moments.
Don’t be sad! Because God sends hope in the most desperate moments.
Haidar oyó decir a un discípulo:‘Estoy contento de no haber comprado tal libro, ya que ahora he llegado a la fuente de su conocimiento y me he ahorrado un esfuerzo y un gasto innecesario.’Luego de un año, Haidar le dio un libro, diciendo:‘Me has servido durante doce meses. El valor de tu labor ha sido de cien dírhams: ese es el precio de este libro.‘Tú no habrías pagado cien monedas de plata por un objeto inanimado como un libro, y poca gente lo haría. Pero yo te he hecho pagar por él, y aquí lo tienes. ‘Un camello es caro por una moneda si no necesitas un camello. ‘Una sola palabra es barata por mil monedas de oro, si es esencial para ti. ‘Si deseas regresar a la Fuente del Ser, siempre tendrás que dar el primer paso, incluso aunque estés pidiendo permiso para dar el paso número cien.
’Pensadores de Oriente
Ya está disponible la nueva traducción, en formato impreso + eBook + audiolibro. Puedes también leerlo gratuitamente aquí:https://idriesshahfoundation.org/…/thinkers-of-the-east
Could photons, light particles, really condense? And how will this “liquid light” behave? Condensed light is an example of a Bose-Einstein condensate: The theory has been there for 100 years, but University of Twente researchers have now demonstrated the effect even at room temperature. For this, they created a micro-size mirror with channels in which photons actually flow like a liquid. In these channels, the photons try to stay together as group by choosing the path that leads to the lowest losses, and thus, in a way, demonstrate “social behavior.” The results are published in Nature Communications.
A Bose-Einstein condensate (BEC) is typically a sort of wave in which the separate particles can not be seen anymore: There is a wave of matter, a superfluid that typically is formed at temperatures close to absolute zero. Helium, for example, becomes a superfluid at those temperatures, with remarkable properties. The phenomenon was predicted by Albert Einstein almost 100 years ago, based on the work of Satyendra Nath Bose; this state of matter was named for the researchers. One type of elementary particle that can form a Bose-Einstein condensate is the photon, the light particle. UT researcher Jan Klärs and his team developed a mirror structure with channels. Light traveling through the channels behaves like a superfluid and also moves in a preferred direction. Extremely low temperatures are not required in this case, and it works at room temperature.
The structure is the well-known Mach-Zehnder interferometer, in which a channel splits into two channels, and then rejoins again. In such interferometers, the wave nature of photons manifests, in which a photon can be in both channels at the same time. At the reunification point, there are now two options: The light can either take a channel with a closed end, or a channel with an open end. Jan Klärs and his team found that the liquid decides for itself which path to take by adjusting its frequency of oscillation. In this case, the photons try to stay together by choosing the path that leads to the lowest losses—the channel with the closed end. You could call it “social behavior,” according to researcher Klärs. Other types of bosons, like fermions, prefer staying separate.
The mirror structure somewhat resembles that of a laser, in which light is reflected back and forth between two mirrors. The major difference is in the extremely high reflection of the mirrors: 99.9985 percent. This value is so high that photons don’t get the chance to escape; they will be absorbed again. It is in this stadium that the photon gas starts taking the same temperature as room temperature via thermalization. Technically speaking, it then resembles the radiation of a black body: Radiation is in equilibrium with matter. This thermalization is the crucial difference between a normal laser and a Bose-Einstein condensate of photons.
In superconductive devices at which the electrical resistance becomes zero, Bose-Einstein condensates play a major role. The photonic microstructures now presented could be used as basic units in a system that solves mathematical problems like the Traveling Salesman problem. But primarily, the paper shows insight into yet another remarkable property of light.
New research by a City College of New York team has uncovered a novel way to combine two different states of matter. For one of the first times, topological photons—light—has been combined with lattice vibrations, also known as phonons, to manipulate their propagation in a robust and controllable way.
The study utilized topological photonics, an emergent direction in photonics which leverages fundamental ideas of the mathematical field of topology about conserved quantities—topological invariants—that remain constant when altering parts of a geometric object under continuous deformations. One of the simplest examples of such invariants is number of holes, which, for instance, makes donut and mug equivalent from the topological point of view. The topological properties endow photons with helicity, when photons spin as they propagate, leading to unique and unexpected characteristics, such as robustness to defects and unidirectional propagation along interfaces between topologically distinct materials. Thanks to interactions with vibrations in crystals, these helical photons can then be used to channel infrared light along with vibrations.
The implications of this work are broad, in particular allowing researchers to advance Raman spectroscopy, which is used to determine vibrational modes of molecules. The research also holds promise for vibrational spectroscopy—also known as infrared spectroscopy—which measures the interaction of infrared radiation with matter through absorption, emission, or reflection. This can then be utilized to study and identify and characterize chemical substances.
“We coupled helical photons with lattice vibrations in hexagonal boron nitride, creating a new hybrid matter referred to as phonon-polaritons,” said Alexander Khanikaev, lead author and physicist with affiliation in CCNY’s Grove School of Engineering. “It is half light and half vibrations. Since infrared light and lattice vibrations are associated with heat, we created new channels for propagation of light and heat together. Typically, lattice vibrations are very hard to control, and guiding them around defects and sharp corners was impossible before.”
The new methodology can also implement directional radiative heat transfer, a form of energy transfer during which heat is dissipated through electromagnetic waves.
“We can create channels of arbitrary shape for this form of hybrid light and matter excitations to be guided along within a two-dimensional material we created,” added Dr. Sriram Guddala, postdoctoral researcher in Prof. Khanikaev’s group and the first author of the manuscript. “This method also allows us to switch the direction of propagation of vibrations along these channels, forward or backward, simply by switching polarizations handedness of the incident laser beam. Interestingly, as the phonon-polaritons propagate, the vibrations also rotate along with the electric field. This is an entirely novel way of guiding and rotating lattice vibrations, which also makes them helical.”
Entitled “Topological phonon-polariton funneling in midinfrared metasurfaces,” the study appears in the journal Science.
Scientists have long known that light can behave as both a particle and a wave—Einstein first predicted it in 1909. But no experiment has been able to show light in both states simultaneously. Now, researchers at the École Polytechnique Fédérale de Lausanne in Switzerland have taken the first ever photograph of light as both a wave and a particle. The key was a new experimental technique that uses electrons to capture the light’s movement. The work was published today in the journal Nature Communications.
To get this snapshot, the researchers shot laser pulses at a nanowire. The wavelengths of light moved in two different directions along the metal. When the waves ran into each other, they look liked a wave standing still, which is effectively a particle.
In order to see how the waves were moving, the researchers shot a beam of electrons at the nanowire, like dropping dye in a river to see the currents. The particles in the light wave changed the speed at which the electrons moved. That enabled the researchers to capture an image just as the waves met.
“This experiment demonstrates that, for the first time ever, we can film quantum mechanics – and its paradoxical nature – directly,” said Fabrizio Carbone, one of the authors of the study, in a press release. Carbone hopes that a better understanding of how light functions can jumpstart the field of quantum computing.
Link Original: https://www.popsci.com/light-photographed-wave-and-particle-first-time/?utm_campaign=trueAnthem%3A%20Trending%20Content&utm_medium=trueAnthem&utm_source=facebook&fbclid=IwAR1bnEcplHEvfb3UOKE8iYXeYqoC_JI1OWMhVKc2tbL4oQ9uvxfW5mkM1BQ
Theory and experiments have shown that future quantum computers will harness the peculiar properties of quantum mechanics to go above and beyond what is currently possible with even the most powerful supercomputers.
These quantum computers will communicate through the quantum internet, which is not as easy as plugging them into the phone line. One crucial requirement in quantum computing is that the particles that perform the calculations are entangled, a quantum mechanical phenomenon where they become part of a single state. A change to one of the particles creates instantaneous changes to the others no matter how far apart they are.
These entangled states are easily disrupted, unfortunately. So how can they be sent between computers to communicate? That’s where quantum teleportation comes in. The entangled state is transferred between two particles. This technique is not perfectly efficient, and scientists are working hard in trying to make the whole process more successful.
A team of researchers from multiple organizations has reported a record-breaking achievement in PRX Quantum. They were able to deliver sustained, long-distance teleportation of qubits (quantum bits) with a fidelity greater than 90% over a fiber-optic network distance of 44 kilometers (27 miles).
“We’re thrilled by these results,” co-author Panagiotis Spentzouris, head of the Fermilab quantum science program, said in a statement. “This is a key achievement on the way to building a technology that will redefine how we conduct global communication.”
Quantum teleportation doesn’t work like the science fiction popularization of teleportation. What you are teleporting is the state of particles via a quantum channel and a classical channel. The sender has the original qubit. This is made to interact with one particle in an entangled pair, producing “classical signal” information about the state of the original qubit. This signal and the other half of that entangled pair are sent to the receiver, and by putting it together, the receiver can recreate the original qubit.
This success is the result of a collaboration between Fermilab, AT&T, Caltech, Harvard University, NASA Jet Propulsion Laboratory, and the University of Calgary. The systems on which this quantum teleportation was achieved were created by Caltech’s public-private research program on Intelligent Quantum Networks and Technologies, or IN-Q-NET.
“We are very proud to have achieved this milestone on sustainable, high-performing and scalable quantum teleportation systems,” explained Maria Spiropulu, the Shang-Yi Ch’en professor of physics at Caltech and director of the IN-Q-NET research program. “The results will be further improved with system upgrades we are expecting to complete by the second quarter of 2021.”
Quantum computers are not here yet, but having the infrastructure to make them work is crucial. The U.S. Department of Energy published its roadmap for a national quantum internet, last July.