Milcom Monitoring Post: Can You ID This Digital Transmission?
Tuesday, March 27, 2012
Tuesday, July 19, 2011
110 nanoseconds of oblivion
Demonstration of temporal cloaking
Authors: Moti Fridman, Alessandro Farsi, Yoshitomo Okawachi, Alexander L. Gaeta
(Submitted on 11 Jul 2011)
Abstract: Recent research has uncovered a remarkable ability to manipulate and control electromagnetic fields to produce effects such as perfect imaging and spatial cloaking. To achieve spatial cloaking, the index of refraction is manipulated to flow light from a probe around an object in such a way that a "hole" in space is created, and it remains hidden. Alternatively, it may be desirable to cloak the occurrence of an event over a finite time period, and the idea of temporal cloaking was proposed in which the dispersion of the material is manipulated in time to produce a "time hole" in the probe beam to hide the occurrence of the event from the observer. This approach is based on accelerating and slowing down the front and rear parts, respectively, of the probe beam to create a well controlled temporal gap in which the event occurs so the probe beam is not modified in any way by the event. The probe beam is then restored to its original form by the reverse manipulation of the dispersion. Here we present an experimental demonstration of temporal cloaking by applying concepts from the time-space duality between diffraction and dispersive broadening. We characterize the performance of our temporal cloak by detecting the spectral modification of a probe beam due to an optical interaction while the cloak is turned off and on and show that the event is observed when the cloak is turned off but becomes undetectable when the cloak is turned on. These results are a significant step toward the development of full spatio-temporal cloaking.
More here:
First Demonstration of Time Cloaking
Physicists have created a "hole in time" using the temporal equivalent of an invisibility cloak
The device has some limitations. The Cornell time cloak lasts only for 110 nanoseconds--that's not long. And Fridman and co say the best it can achieve will be 120 microseconds.
Authors: Moti Fridman, Alessandro Farsi, Yoshitomo Okawachi, Alexander L. Gaeta
(Submitted on 11 Jul 2011)
Abstract: Recent research has uncovered a remarkable ability to manipulate and control electromagnetic fields to produce effects such as perfect imaging and spatial cloaking. To achieve spatial cloaking, the index of refraction is manipulated to flow light from a probe around an object in such a way that a "hole" in space is created, and it remains hidden. Alternatively, it may be desirable to cloak the occurrence of an event over a finite time period, and the idea of temporal cloaking was proposed in which the dispersion of the material is manipulated in time to produce a "time hole" in the probe beam to hide the occurrence of the event from the observer. This approach is based on accelerating and slowing down the front and rear parts, respectively, of the probe beam to create a well controlled temporal gap in which the event occurs so the probe beam is not modified in any way by the event. The probe beam is then restored to its original form by the reverse manipulation of the dispersion. Here we present an experimental demonstration of temporal cloaking by applying concepts from the time-space duality between diffraction and dispersive broadening. We characterize the performance of our temporal cloak by detecting the spectral modification of a probe beam due to an optical interaction while the cloak is turned off and on and show that the event is observed when the cloak is turned off but becomes undetectable when the cloak is turned on. These results are a significant step toward the development of full spatio-temporal cloaking.
More here:
First Demonstration of Time Cloaking
Physicists have created a "hole in time" using the temporal equivalent of an invisibility cloak
The device has some limitations. The Cornell time cloak lasts only for 110 nanoseconds--that's not long. And Fridman and co say the best it can achieve will be 120 microseconds.
Sunday, July 18, 2010
The Highest Freq Known to Man
... is in the attosecond range.
Firing away 180 attosecond pulses, the Max-Planck-Institut für Quantenoptik has measured the interval between a photon striking an atom and the emission of an electron. And so the record stands: 20 attosecondes.
Verzögerter Zeitpunkt Null
Firing away 180 attosecond pulses, the Max-Planck-Institut für Quantenoptik has measured the interval between a photon striking an atom and the emission of an electron. And so the record stands: 20 attosecondes.
Verzögerter Zeitpunkt Null
Saturday, January 30, 2010
Scanning Beyond SETI
Starry Messages: Searching for Signatures of Interstellar Archaeology
Richard A. Carrigan, Jr.,
Fermi National Accelerator Laboratory
Searching for signatures of cosmic-scale archaeological artifacts such as Dyson spheres or Kardashev civilizations is an interesting alternative to conventional SETI. Uncovering such an artifact does not require the intentional transmission of a signal on the part of the original civilization. This type of search is called interstellar archaeology or sometimes cosmic archaeology. The detection of intelligence elsewhere in the Universe with interstellar archaeology or SETI would have broad implications for science. For example, the constraints of the anthropic principle would have to be loosened if a different type of intelligence was discovered elsewhere. A variety of interstellar archaeology signatures are discussed including non-natural planetary atmospheric constituents, stellar doping with isotopes of nuclear wastes, Dyson spheres, as well as signatures of stellar and galactic-scale engineering. The concept of a Fermi bubble due to interstellar migration is introduced in the discussion of galactic signatures. These potential interstellar archaeological signatures are classified using the Kardashev scale. A modified Drake equation is used to evaluate the relative challenges of finding various sources. With few exceptions interstellar archaeological signatures are clouded and beyond current technological capabilities. However SETI for so-called cultural transmissions and planetary atmosphere signatures are within reach.
Richard A. Carrigan, Jr.,
Fermi National Accelerator Laboratory
Searching for signatures of cosmic-scale archaeological artifacts such as Dyson spheres or Kardashev civilizations is an interesting alternative to conventional SETI. Uncovering such an artifact does not require the intentional transmission of a signal on the part of the original civilization. This type of search is called interstellar archaeology or sometimes cosmic archaeology. The detection of intelligence elsewhere in the Universe with interstellar archaeology or SETI would have broad implications for science. For example, the constraints of the anthropic principle would have to be loosened if a different type of intelligence was discovered elsewhere. A variety of interstellar archaeology signatures are discussed including non-natural planetary atmospheric constituents, stellar doping with isotopes of nuclear wastes, Dyson spheres, as well as signatures of stellar and galactic-scale engineering. The concept of a Fermi bubble due to interstellar migration is introduced in the discussion of galactic signatures. These potential interstellar archaeological signatures are classified using the Kardashev scale. A modified Drake equation is used to evaluate the relative challenges of finding various sources. With few exceptions interstellar archaeological signatures are clouded and beyond current technological capabilities. However SETI for so-called cultural transmissions and planetary atmosphere signatures are within reach.
Tuesday, November 17, 2009
NSA Will Use This II
Quantum Computers Could Tackle Enormous Linear Equations
A new algorithm may give quantum computers a new, practical job: quickly solving monster linear equations. Such problems are at the heart of complex processes such as image and video processing, genetic analyses and even Internet traffic control.
...or Internet traffic scanning and analysis, we should add.
The new work, published October 7 in Physical Review Letters, may dramatically expand the range of potential uses for quantum computers.
A new algorithm may give quantum computers a new, practical job: quickly solving monster linear equations. Such problems are at the heart of complex processes such as image and video processing, genetic analyses and even Internet traffic control.
...or Internet traffic scanning and analysis, we should add.
The new work, published October 7 in Physical Review Letters, may dramatically expand the range of potential uses for quantum computers.
An earlier version of the article: June 2, 2009
In the new study, Aram Harrow of the University of Bristol in England along with Avinatan Hassidim and Seth Lloyd, both of MIT, propose that large datasets of linear equations could be encoded in quantum forms, such as the spins of nuclei, individual atoms or photons. Such a system would allow quantum computers to handily solve problems made up of billions or even trillions of variables...
...thus raising the encryption bar even further. But, in the same issues of of Physical Review Letters and Science News, we find:
Entangled Photons Make Better Messengers
Quantum communication offers an absolutely secure way to send secret messages, such as encoded military secrets or financial transactions. But quantum information is fragile, quickly destroyed by even slight interactions with the environment.
While a conventional bit of information can have only one value, 0 or 1, a quantum bit, or qubit, exists as a combination of 0 and 1 simultaneously. A qubit stays in this undecided state until something, whether a stray atom or a scientist trying to measure its properties, interacts with it, forcing it into a single state. This collapse of possibilities, known as quantum decoherence, can be detected farther down the line to catch eavesdroppers. But it can also keep qubits from reaching their destination intact.
Fortunately, theorists have shown that some quantum-mechanical systems are immune to certain interactions...
Including eavesdropping?
Saturday, October 31, 2009
Wednesday, August 19, 2009
More bio-quantum mechanics...
Zeno is pro Darwin: Quantum Zeno Effect Suppresses the Dependence of Radical-Ion-Pair Reaction Yields on Exchange and Dipolar Interactions
Author: I. K. Kominis
Abstract: A biochemical quantum sensor of magnetic fields, namely magnetic-sensitive radical-ion-pair reactions, is understood to underlie avian magnetic navigation. It has been recently postulated [O. Efimova and P. J. Hore, Biophys. J. {\bf 94}, 1565 (2008)] that a fine-tuned cancellation of exchange and dipolar interactions in necessary for this magnetic sensor to function at earth's field. We here show that if the basic parameters of the radical-ion-pair are such that the quantum Zeno effect is manifested, the dependence of the magnetic-sensitive reaction yields on molecule-specific exchange and dipolar interactions is almost entirely suppressed. A fundamental quantum effect is thus shown to provide for the robustness of this biochemical sensor.
Zeno is pro Darwin: Quantum Zeno Effect Suppresses the Dependence of Radical-Ion-Pair Reaction Yields on Exchange and Dipolar Interactions
Author: I. K. Kominis
Abstract: A biochemical quantum sensor of magnetic fields, namely magnetic-sensitive radical-ion-pair reactions, is understood to underlie avian magnetic navigation. It has been recently postulated [O. Efimova and P. J. Hore, Biophys. J. {\bf 94}, 1565 (2008)] that a fine-tuned cancellation of exchange and dipolar interactions in necessary for this magnetic sensor to function at earth's field. We here show that if the basic parameters of the radical-ion-pair are such that the quantum Zeno effect is manifested, the dependence of the magnetic-sensitive reaction yields on molecule-specific exchange and dipolar interactions is almost entirely suppressed. A fundamental quantum effect is thus shown to provide for the robustness of this biochemical sensor.
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