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Nearly 90 years after Werner Heisenberg pioneered his uncertainty principle, a group of researchers from three countries has provided substantial new insight into this fundamental tenet of quantum physics with the first rigorous formulation supporting the uncertainty principle as Heisenberg envisioned it. In the Journal of Mathematical Physics, the researchers reports a new way of defining measurement errors that is applicable in the quantum domain and enables a precise characterization of the fundamental limits of the information accessible in quantum experiments. Quantum mechanics requires that we devise approximate joint measurements because the theory itself prohibits simultaneous ideal measurements of position...

Physicists have proposed an experiment that could force us to make a choice between extremes to describe the behaviour of the Universe. The proposal comes from an international team of researchers from Switzerland, Belgium, Spain and Singapore, and is published today in Nature Physics. It is based on what the researchers call a 'hidden influence inequality'. This exposes how quantum predictions challenge our best understanding about the nature of space and time, Einstein's theory of relativity. "We are interested in whether we can explain the funky phenomena we observe without sacrificing our sense of things happening smoothly in space and...

n March 2012, Joseph Polchinski began to contemplate suicide — at least in mathematical form. A string theorist at the Kavli Institute for Theoretical Physics in Santa Barbara, California, Polchinski was pondering what would happen to an astronaut who dived into a black hole. Obviously, he would die. But how? According to the then-accepted account, he wouldn’t feel anything special at first, even when his fall took him through the black hole’s event horizon: the invisible boundary beyond which nothing can escape. But eventually — after hours, days or even weeks if the black hole was big enough — he...

Ex nihilo: Dynamical Casimir effect in metamaterial converts vacuum fluctuations into real photons March 8, 2013 by Stuart Mason Dambrot Copyright © PNAS, doi:10.1073/pnas.1212705110 (Phys.org) —In the strange world of quantum mechanics, the vacuum state (sometimes referred to as the quantum vacuum, simply as the vacuum) is a quantum system's lowest possible energy state. While not containing physical particles, neither is it an empty void: Rather, the quantum vacuum contains fluctuating electromagnetic waves and so-called virtual particles, the latter being known to transition into and out of existence. In addition, the vacuum state has zero-point energy – the lowest quantized...

Scientists create never-before-seen form of matter Photons with strong mutual attraction in a quantum nonlinear medium. Harvard and MIT scientists are challenging the conventional wisdom about light, and they didn't need to go to a galaxy far, far away to do it. Working with colleagues at the Harvard-MIT Center for Ultracold Atoms, a group led by Harvard Professor of Physics Mikhail Lukin and MIT Professor of Physics Vladan Vuletic have managed to coax photons into binding together to form molecules – a state of matter that, until recently, had been purely theoretical. The work is described in a September 25...

A book titled “Biocentrism: How Life and Consciousness Are the Keys to Understanding the Nature of the Universe“ has stirred up the Internet, because it contained a notion that life does not end when the body dies, and it can last forever. The author of this publication, scientist Dr. Robert Lanza who was voted the 3rd most important scientist alive by the NY Times, has no doubts that this is possible.[...]The theory implies that death of consciousness simply does not exist. It only exists as a thought because people identify themselves with their body. They believe that the body is...

All of the matter in the universe—everything we see, feel and smell—has a certain predictable structure, thanks to the tiny electrons spinning around their atomic nuclei in a series of concentric shells or atomic levels. A fundamental tenet of this orderly structure is that no two electrons can occupy the same atomic level (quantum state) at the same time—a principle called the Pauli exclusion principle, which is based on Albert Einstein’s theory of relativity and quantum theory. However, a team of Syracuse University physicists recently developed a new theoretical model to explain how the Pauli exclusion principle can be violated...

Almost a century ago, renowned quantum theorist Werner Heisenberg found fundamental limits on how well a quantum system can be prepared and measured, known as Heisenberg's uncertainty principle. However, only the limit that pertains to the preparation of quantum systems has been quantified; the other two, relating to measurements, have long been a matter of debate, lacking a formal treatment. These limits are: That it is impossible to jointly measure incompatible quantities, for instance, location and speed of a quantum object, with perfect accuracy; and that a measurement of one of these quantities necessarily disturbs the other. Last year, UQ's...

In a paper published in the current issue of the scientific journal Nature Communications and titled "Direct measurement of a 27-dimensional orbital-angular-momentum state vector," a team of physicists led by the University of Rochester's Mehul Malik describe how they circumvented a basic principle of uncertainty that requires that some states of a quantum system must be understood poorly if other states are to be understood well. Determining a quantum state, such as the position of an electron or the momentum of a photon, is tricky, to say the least. That's because subatomic particles behave nothing at all like billiard balls,...

Government Lab Reveals It Has Operated Quantum Internet for Over Two Years A quantum internet capable of sending perfectly secure messages has been running at Los Alamos National Labs for the last two and a half years, say researchers One of the dreams for security experts is the creation of a quantum internet that allows perfectly secure communication based on the powerful laws of quantum mechanics.The basic idea here is that the act of measuring a quantum object, such as a photon, always changes it. So any attempt to eavesdrop on a quantum message cannot fail to leave telltale signs...

This article is in honor or the opening of the latest session of the Supreme Court. There is a famous law in Physics known as Heisenberg’s uncertainty principle. If you have only heard of it in the mainstream press, you may have heard of it incorrectly. Some think it means that you cannot tell where anything is – like your car keys, or the last pair of socks in the dryer, only worse. The actual scientific definition is more complicated, and it says that you cannot simultaneously know the position and the momentum of a particle with infinite precision; in...

Why Quantum Mechanics Is Not So Weird after All Richard Feynman's "least-action" approach to quantum physics in effect shows that it is just classical physics constrained by a simple mechanism. When the complicated mathematics is left aside, valuable insights are gained. PAUL QUINCEY The birth of quantum mechanics can be dated to 1925, when physicists such as Werner Heisenberg and Erwin Schrödinger invented mathematical procedures that accurately replicated many of the observed properties of atoms. The change from earlier types of physics was dramatic, and pre-quantum physics was soon called classical physics in a kind of nostalgia for the...

<p>Warner Heisenberg would understand the current media confusion surrounding the progress of the war. About 80 years ago, the German physicist postulated a theory — known as the Uncertainty Principle — that in sub-atomic physics the observer becomes part of the observed system. Through the act of measurement the physicist becomes himself part of observed reality. Regarding subatomic particles, he argued, the act of measuring one magnitude of a particle — mass, velocity or position — causes the other magnitudes to blur. So that, in his words: "The more precisely the position is determined, the less precisely the momentum is known."</p>

    "Exact uncertainty" brought to quantum world   00:01 27 April 02   Exclusive from New Scientist Print Edition   Exact uncertainty sounds like a contradiction in terms, but that is what governs the quantum world, according to a theoretical physicist who has created an improved version of the famous Heisenberg uncertainty principle. Heisenberg worked out that there is a degree of inherent fuzziness to the world. You cannot measure both the position and the momentum of any particle with perfect accuracy. The better the accuracy of your momentum measurement, the more uncertain your position measurement must be, and vice versa....