Articles by David Appell
Phys.org / A device to sort photon states could be useful for quantum optical computer circuits
To build light-based quantum technologies, scientists and engineers need the ability to generate and manipulate photons as individuals or a few at a time. To build such quantum photonic logic gates that might be used in an ...
Phys.org / Using a gamma ray burst to search for violations of Einstein's relativity postulates
Einstein's theory of relativity is based on two assumptions, or postulates. The first is that the laws of physics look the same to everyone traveling in a straight line with no acceleration.
Phys.org / Using atomic excitations to measure the rotation of spacetime
How would atoms behave near a supermassive object? We know how atoms behave in extremely weak gravity like that at the Earth's surface: They can be excited from a lower energy level to a higher one when an electron absorbs ...
Phys.org / In the hunt for alien life, is man truly 'the measure of all things?'
Enrico Fermi's lunchtime question at wartime Los Alamos, "Where is everybody?" has been both a gift and a problem to scientists ever since. Known as "Fermi's Paradox," it simply asks, why, since life on Earth is ubiquitous ...
Phys.org / Test of a prototype quantum internet runs under New York City for half a month
To introduce quantum networks into the marketplace, engineers must overcome the fragility of entangled states in a fiber cable and ensure the efficiency of signal delivery. Now, scientists at Qunnect Inc. in Brooklyn, New ...
Phys.org / A maximally entangled quantum state with a fixed spectrum does not exist in the presence of noise, mathematician claims
For more than 20 years, quantum researchers have wondered whether a quantum system can have maximum entanglement in the presence of noise. A mathematician from Spain recently answered the question: No.
Phys.org / Corrected sunspot records show the Maunder minimum did not end abruptly
How accurate are past records of sunspots? In a new study published in The Astrophysical Journal, a team of multinational researchers examined the historical record and found that after the unusual period of almost no sunspots, ...
Phys.org / Photon entanglement could explain the rapid brain signals behind consciousness
Understanding the nature of consciousness is one of the hardest problems in science. Some scientists have suggested that quantum mechanics, and in particular quantum entanglement, is the key to unraveling the phenomenon.
Phys.org / Study reports dim odds for finding alien civilizations
Are there any advanced alien civilizations elsewhere in our galaxy? We don't know. All we do know is that there is at least one. Should we be optimistic or pessimistic about finding others?
Phys.org / New technique measures superconductivity at very high pressures
In 1911, Heike Kamerlingh Onnes discovered the first superconductor, metallic mercury when cooled to a critical temperature of 4.2 Kelvin, where it conducts electricity without resistance. Ever since materials scientists ...
Phys.org / The major Atlantic current that keeps Northern Europe warm could have new variations and tipping points
Northern Europe is relatively warm given its place on the globe. For example, although north of most major Canadian cities, London is warmer than all of them (even Vancouver in British Columbia). But this warmth could disappear ...
Tech Xplore / A passive, renewable, more efficient way to extract water from the atmosphere
Freshwater scarcity affects over two billion people in the world, primarily in arid and remote regions, as well as islands and coastal areas without freshwater sources. Climate change and population growth are only making ...
Phys.org / Creation of a deep learning algorithm to detect unexpected gravitational wave events
Starting with the direct detection of gravitational waves in 2015, scientists have relied on a bit of a kludge: they can only detect those waves that match theoretical predictions, which is rather the opposite way that science ...
Phys.org / Study shows elephant trunk dexterity can be mimicked with minimal actuators
The trunk of an elephant is among the versatile appendages in the animal kingdom. Now a research team has shown that most of its dexterity can be reproduced with a model using just three "muscles." And they built a physical ...
Phys.org / The Milky Way's eROSITA bubbles are large and distant
In 2020, astronomers discovered a large hourglass-shaped structure in or near the center of our Milky Way galaxy. Dubbed "eROSITA bubbles," there have been a few different hypotheses proposed to explain their precise nature. ...
