What is quantum superposition Quantum matter can be difficult to study. While physicists have come a long way in the research of this microscopic science, some things are still a mystery because quantum matter can behave so erratically. Einstein's theory of relativity and various other laws of physics tend to fall apart at the subatomic level of quantum physics, because photons -- or tiny particles of light -- seem to change form randomly, and possibly change simply in observation.
Not Even Wrong While I was away on vacation, the big news in physics was the BICEP2 result on B-modes in the CMB. Maybe it’s just as well I wasn’t available to blog about this, since inflation and cosmology aren’t at all my field of expertise. Now that some of the dust has settled from the media blitz though, I do think it’s worth while to write something here, since there are some aspects of the story where the media coverage could use some extra perspective. First of all, there’s the obligatory caveat about this result not being definitive, which most coverage by scientists has included. To my non-expert eye, looking at the main graph reproduced everywhere, if you subtract the gravitational lensing background you get something which is much larger at higher values of l than it is supposed to be if it were coming from primordial gravitational waves.
Dimension The first four spatial dimensions. In mathematics In mathematics, the dimension of an object is an intrinsic property independent of the space in which the object is embedded. For example, a point on the unit circle in the plane can be specified by two Cartesian coordinates, but a single polar coordinate (the angle) would be sufficient, so the circle is 1-dimensional even though it exists in the 2-dimensional plane.
Reading List: Feynman Lectures on Gravitation (Fourmilog: None Dare Call It Reason) In the 1962–63 academic year at Caltech, Richard Feynman taught a course on gravitation for graduate students and postdoctoral fellows. For many years the blackboard in Feynman's office contained the epigram, “What I cannot create, I do not understand.” In these lectures, Feynman discards the entire geometric edifice of Einstein's theory of gravitation (general relativity) and starts from scratch, putting himself and his students in the place of physicists from Venus (who he calls “Venutians”—Feynman was famously sloppy with spelling: he often spelled “gauge” as “guage”) who have discovered the full quantum theories of electromagnetism and the strong and weak nuclear forces but have just discovered there is a very weak attractive force between all masses, regardless of their composition. A spin 2 graviton implies a field with a tensor potential function, and from the behaviour of gravitation we know that the tensor must be symmetric. This book is a period piece.
Perth, Western Australia As part of Perth's role as the capital of Western Australia, the state's Parliament and Supreme Court are located within the city, as well as Government House, the residence of the Governor of Western Australia. Perth became known worldwide as the "City of Light" when city residents lit their house lights and streetlights as American astronaut John Glenn passed overhead while orbiting the earth on Friendship 7 in 1962. The city repeated the act as Glenn passed overhead on the Space Shuttle in 1998. Perth came 9th in the Economist Intelligence Unit's August 2012 list of the world's most liveable cities, and was classified by the Globalization and World Cities Research Network in 2010 as a world city. History Indigenous history
Quantum cryptography Quantum cryptography uses our current knowledge of physics to develop a cryptosystem that is not able to be defeated - that is, one that is completely secure against being compromised without knowledge of the sender or the receiver of the messages. The word quantum itself refers to the most fundamental behavior of the smallest particles of matter and energy: quantum theory explains everything that exists and nothing can be in violation of it. Quantum cryptography is different from traditional cryptographic systems in that it relies more on physics, rather than mathematics, as a key aspect of its security model. Essentially, quantum cryptography is based on the usage of individual particles/waves of light (photon) and their intrinsic quantum properties to develop an unbreakable cryptosystem - essentially because it is impossible to measure the quantum state of any system without disturbing that system. How It Works in Theory Bob measures some photons correctly and others incorrectly.