Category Archives: Quantum Mechanics

On the nature of time in string theory

The journal Foundations of Physics commemorates “Forty Years of String Theory.” Vijay Balasubramanian (University of Pennsylvania) steps back and ask what we do not understand about time. What is time?  Within the broader quantum gravity community outside string theory there has … Continue reading

Posted in Cosmology, Mathematics, Physics, Quantum Mechanics, Science, String Theory | Tagged , , , | 2 Comments

A single photon can be in as many as four places at the same time

Vladan Vuletic, “Quantum physics: Entangled quartet,” News & Views, Nature 468: 384–385, 18 November 2010, summarizes the paper K. S. Choi, A. Goban, S. B. Papp, S. J. van Enk & H. J. Kimble, “Entanglement of spin waves among four … Continue reading

Posted in Optics, Physics, Quantum Mechanics, Science, Uncategorized | Tagged , , | 7 Comments

Aspelmeyer in Nature, “Quantum mechanics: The surf is up”

“Researchers have long wanted to be able to control macroscopic mechanical objects in their smallest possible state of motion. Success in achieving that goal heralds a new generation of quantum experiments.” Markus Aspelmeyer, “Quantum mechanics: The surf is up,” News … Continue reading

Posted in News, Physics, Quantum Mechanics, Science | Tagged , | Leave a comment

Quantum entanglement in a macroscopic system at high temperatures

“Quantum entanglement has been observed at low temperatures in both microscopic and macroscopic systems. It now seems that the effect can also occur at high temperatures if the systems are not in thermal equilibrium.” The spanish scientist Fernando Galve and … Continue reading

Posted in News, Quantum Mechanics, Science | Tagged , , | Leave a comment

Hohenberg, “Consistent quantum theory,” or Copenhagen done right!

Consistent quantum theory (CQT) was introduced over 25 years ago by Robert Griffiths (1984), and further elaborated by Gell-Mann and Hartle (1993). This theory is a version of orthodox quantum mechanics based in the principle of complementarity. Complementarity is the essence of quantum … Continue reading

Posted in Physics, Quantum Mechanics, Science | Tagged , | 1 Comment

Quantum computers protected by space-time cloaking devices

Quantum computers are very fragile devices, the accidental observation of any quantum property can disrupt calculations before they have been completed. ¿Could a quantum computer be hidden inside a protecting spatiotemporal cloaking device? Such is the proposal of Ortwin Hess, a researcher … Continue reading

Posted in News, Optics, Physics, Quantum Computers, Quantum Mechanics, Science, Theoretical Proposal | Tagged , | 2 Comments