Sunday is upon us again and it’s time to have a look at what’s been going on in the world of science. Here are the top news plus some links for extra reading. To subscribe to these news and other posts and videos, visit this link.
Recent Stephen Hawking’s statements on the physics of black holes have gained a lot of attention in the press so let’s see what is this is all about. Black holes can be studied from the point of view of classical physics to some extent, however, modern treatment of these exotic objects dates back to 1915 when Einstein derived his famous equations of general relativity. Karl Schwarzschild was the first person to find an exact solution to these equations, which described the gravitational field outside a spherical mass distribution. An interesting consequence of Schwarzschild solutions was that, if there is enough mass, the gravitational field could become so strong that nothing could escape. This is known as a black hole.
A few decades later, when quantum mechanics was developed, scientists started wondering if black holes could be described using the exotic theory. And, surprisingly, it turned out to be much harder than expected — the theory of general relativity simply was not compatible with quantum mechanics. One of the most famous attempts to tackle this problem came from Stephen Hawking, who showed that black holes “leaked” radiation.
Another strange thing about black holes was their tendency to destroy any information of what has fallen through the event horizon. This idea is very uncomfortable to quantum physicists, who would like it if the information of what has fallen inside would be somehow obtainable. And this is where one of the most interesting solutions by Joseph Polchinski comes in. The US physicist theorized that the information about the objects, which have fallen into the black hole is not lost, but is retrievable through the black hole radiation. However, to “record” information of the in-falling objects, the black hole, according to the equations derived by Polchinski, has to be surrounded by a high energy “firewall”. This, however, contradicts the ideas from GR, which state that an in-falling object should feel nothing different when falling through the event horizon.
To solve this quandary, Stephen Hawking, in his recent paper, theorized that the event horizon should be changed to an “apparent horizon”, which captures matter and radiation, but does so only temporally. After a certain period of time, matter and radiation are released. This, in words of Hawking, makes “firewalls” unnecessary, but, at the same time, does not violate GR.
Black holes might not be so black after all
Magnetic monopoles were first predicted to exist by the famous physicist Paul Dirac in 1931 and remained elusive for a very long time. Recently, however, a team from Aalto University, Finland, and Amherst College, US have shown that synthetic monopoles exist after all. “Our work provides conclusive and long-awaited experimental evidence of the existence of Dirac monopoles.It provides an unprecedented opportunity to observe and manipulate these quantum mechanical entities in a controlled environment,” said the members of the team. To find out more use the link above.
The prospect of integrating living organisms into a non-living substrate has always been appealing for those investigating active matter. Recently, scientists at Kent State University, Argonne National Laboratory and Northwestern University have proposed the living liquid crystal (LLC) – a new class of active matter. The researchers found that the novel material displays a wide range of useful and occasionally surprising properties that lend themselves to a wide array of potential biosensing, biomedical, submicrometer, autonomous microprobe, and structural imaging applications. To find out more use the link above.
Knowing about all the bad press that NSA has been getting recently it’s not a surprise that the news of NSA working towards a quantum computer were received with an uproar. In particular, documents leaked by Edward Snowden talked about a project dubbed “Penetrating Hard Targets”, which was all about using quantum technologies to crack modern internet security systems. This could be achieved by factorizing huge numbers in a very short time, thus quickly deciphering encryption keys.
For NSA such a technology could mean deciphering banking transactions, private messages and government files. For most physicists, computer scientists and mathematicians, however, this illustrates a growing need to stay ahead of the game and develop more sophisticated encryption techniques. An example of such technique would be Quantum key distribution.