07-20-2010, 11:17 AM
Quantum Time Machine Solves Grandfather Paradox
be well,be love.
quantum time machine solves grandfather paradox
a new kind of time travel based on quantum teleportation gets around the paradoxes that have plagued other time machines, say physicists.
of all the weird consequences of quantum mechanics, one of the strangest is the notion of postselection: the ability to trigger a computation that automatically disregards certain results.
here's an example: suppose you have a long, tortuous expression in which there are a frighteningly large number of variables. the question you want answering is which combination of variables makes the expression logically true. and the conventional way to solve it is by brute force: try every combination of variable until you find one that works. that's hard.
postselection, however, makes the solution easy to find. simply allow the variables to take any value at random and then postselect on the condition that the answer must be true. this automatically disregards any wrong'uns that come up.
07-20-2010, 05:49 PM
Time Does Not Exist
“one finds that time just disappears from the wheeler-dewitt equation,” says carlo rovelli, a physicist at the university of the mediterranean in marseille, france. “it is an issue that many theorists have puzzled about. it may be that the best way to think about quantum reality is to give up the notion of time—that the fundamental description of the universe must be timeless.”
no one has yet succeeded in using the wheeler-dewitt equation to integrate quantum theory with general relativity. nevertheless, a sizable minority of physicists, rovelli included, believe that any successful merger of the two great masterpieces of 20th-century physics will inevitably describe a universe in which, ultimately, there is no time.
the possibility that time may not exist is known among physicists as the “problem of time.” it may be the biggest, but it is far from the only temporal conundrum. vying for second place is this strange fact: the laws of physics don’t explain why time always points to the future. all the laws—whether newton’s, einstein’s, or the quirky quantum rules—would work equally well if time ran backward. as far as we can tell, though, time is a one-way process; it never reverses, even though no laws restrict it.
07-21-2010, 02:18 PM
Benoit Mandelbrot: Fractals and the art of roughness
be well, be love.
at ted2010, mathematics legend benoit mandelbrot develops a theme he first discussed at ted in 1984 -- the extreme complexity of roughness, and the way that fractal math can find order within patterns that seem unknowably complicated.
07-26-2010, 07:37 AM
LHC firing on all cylinders
lhc firing on all cylinders, but no higgs boson yet
that's the report monday from the international conference on high-energy physics in paris, where lhc researchers announced they've successfully retraced the steps of earlier particle accelerators. the final step was the a likely view of a super-heavy and short-lived particle called the top quark, first seen in 1995 at fermilab's tevatron accelerator near chicago.
"they have re-found all the known particles in the standard model," the successful but ultimately insufficient explanation that physicists use to catalog fundamental particles, said rolf heuer, director general of the cern laboratory in geneva that houses the massive particle accelerator. "the experiments have shown they are ready for new physics once new physics will appear," he told reporters at the conference.
the elusive higgs boson, a predicted but as yet unobserved particle thought to imbue other particles with gravity, remains unseen--but at the present stage of getting the lhc up to speed, that was no surprise. but it's clear the lhc, despite its troubled start-up and the fact that it's not expected to start running at full power for years, has begun carrying the baton for particle physics.
07-30-2010, 10:29 AM
buckyballs -- the 60-carbon buckminsterfullerenes known for their soccer ball shape -- may occur naturally in space, according to two research groups.
the recent reports offer data supporting the contention that the spherical carbonaceous shells, known to occur naturally on earth, can also form in the inky void of space.
in the may 5 [n.sub.ature], Unknownpo radicati di brozolo, a apace scientist at charles evans and associates in redwood city, calif., and his colleagues describe finding fullerenes among carbon residue in a tiny impact crater on nasa's long-duration exposure facility after that spacecraft's return to earth.
08-10-2010, 10:34 AM
Rethinking Einstein: The end of space-time
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rethinking einstein: the end of space-time
* 09 august 2010 by anil ananthaswamy
physicists struggling to reconcile gravity with quantum mechanics have hailed a theory – inspired by pencil lead – that could make it all very simple
it was a speech that changed the way we think of space and time. the year was 1908, and the german mathematician hermann minkowski had been trying to make sense of albert einstein's hot new idea - what we now know as special relativity - describing how things shrink as they move faster and time becomes distorted. "henceforth space by itself and time by itself are doomed to fade into the mere shadows," minkowski proclaimed, "and only a union of the two will preserve an independent reality."
and so space-time - the malleable fabric whose geometry can be changed by the gravity of stars, planets and matter - was born. it is a concept that has served us well, but if physicist petr horava is right, it may be no more than a mirage. horava, who is at the university of california, berkeley, wants to rip this fabric apart and set time and space free from one another in order to come up with a unified theory that reconciles the disparate worlds of quantum mechanics and gravity - one the most pressing challenges to modern physics.
since horava published his work in january 2009, it has received an astonishing amount of attention. already, more than 250 papers have been written about it. some researchers have started using it to explain away the twin cosmological mysteries of dark matter and dark energy. others are finding that black holes might not behave as we thought. if horava's idea is right, it could forever change our conception of space and time and lead us to a "theory of everything", applicable to all matter and the forces that act on it.
if petr horava's idea is right, it could change our conception of space and time forever
for decades now, physicists have been stymied in their efforts to reconcile einstein's general theory of relativity, which describes gravity, and quantum mechanics, which describes particles and forces (except gravity) on the smallest scales. the stumbling block lies with their conflicting views of space and time. as seen by quantum theory, space and time are a static backdrop against which particles move. in einstein's theories, by contrast, not only are space and time inextricably linked, but the resulting space-time is moulded by the bodies within it.
part of the motivation behind the quest to marry relativity and quantum theory - to produce a theory of quantum gravity - is an aesthetic desire to unite all the forces of nature. but there is much more to it than that. we also need such a theory to understand what happened immediately after the big bang or what's going on near black holes, where the gravitational fields are immense.
one area where the conflict between quantum theory and relativity comes to the fore is in the gravitational constant, g, the quantity that describes the strength of gravity. on large scales - at the scale of the solar system or of the universe itself - the equations of general relativity yield a value of g that tallies with observed behaviour. but when you zoom in to very small distances, general relativity cannot ignore quantum fluctuations of space-time. take them into account and any calculation of g gives ridiculous answers, making predictions impossible.
08-19-2010, 12:15 PM
Inexplicable Superconductor Fractals Hint at Higher Universal Laws
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inexplicable superconductor fractals hint at higher universal laws
* by brandon keim email author
* august 11, 2010
what seemed to be flaws in the structure of a mystery metal may have given physicists a glimpse into as-yet-undiscovered laws of the universe.
the qualities of a high-temperature superconductor — a compound in which electrons obey the spooky laws of quantum physics, and flow in perfect synchrony, without friction — appear linked to the fractal arrangements of seemingly random oxygen atoms.
those atoms weren’t thought to matter, especially not in relation to the behavior of individual electrons, which exist at a scale thousands of times smaller. the findings, published aug. 12 in nature, are a physics equivalent of discovering a link between two utterly separate dimensions.
“we don’t know the theory for this,” said physicist antonio bianconi of rome’s sapienza university. “we just make the experimental observation that the two worlds seem to interfere.”
08-26-2010, 10:53 AM
Back From the Future
click the link to access the links.
back from the future
be well, be love.
back from the future
a series of quantum experiments shows that measurements performed in the future can influence the present. does that mean the universe has a destiny—and the laws of physics pull us inexorably toward our prewritten fate?
by zeeya merali; photography by adam magyar
from the april 2010 issue; published online august 26, 2010
also see the other articles in this issue's special beyond einstein section: is the search for immutable laws of nature a wild-goose chase and the mystery of the rocketing particles that shouldn't exist.
jeff tollaksen may well believe he was destined to be here at this point in time. we’re on a boat in the atlantic, and it’s not a pleasant trip. the torrential rain obscures the otherwise majestic backdrop of the volcanic azorean islands, and the choppy waters are causing the boat to lurch. the rough sea has little effect on tollaksen, barely bringing color to his nordic complexion. this is second nature to him; he grew up around boats. everyone would agree that events in his past have prepared him for today’s excursion. but tollaksen and his colleagues are investigating a far stranger possibility: it may be not only his past that has led him here today, but his future as well.
tollaksen’s group is looking into the notion that time might flow backward, allowing the future to influence the past. by extension, the universe might have a destiny that reaches back and conspires with the past to bring the present into view. on a cosmic scale, this idea could help explain how life arose in the universe against tremendous odds. on a personal scale, it may make us question whether fate is pulling us forward and whether we have free will.
the boat trip has been organized as part of a conference sponsored by the foundational questions institute to highlight some of the most controversial areas in physics. tollaksen’s idea certainly meets that criterion. and yet, as crazy as it sounds, this notion of reverse causality is gaining ground. a succession of quantum experiments confirm its predictions—showing, bafflingly, that measurements performed in the future can influence results that happened before those measurements were ever made.
as the waves pound, it’s tough to decide what is more unsettling: the boat’s incessant rocking or the mounting evidence that the arrow of time—the flow that defines the essential narrative of our lives—may be not just an illusion but a lie.
tollaksen, currently at chapman university in orange county, california, developed an early taste for quantum mechanics, the theory that governs the motion of particles in the subatomic world. he skipped his final year of high school, instead attending physics lectures by the charismatic nobel laureate richard feynman at caltech in pasadena and learning of the paradoxes that still fascinate and frustrate physicists today.
primary among those oddities was the famous uncertainty principle, which states that you can never know all the properties of a particle at the same time. for instance, it is impossible to measure both where the particle is and how fast it is moving; the more accurately you determine one aspect, the less precisely you can measure the other. at the quantum scale, particles also have curiously split personalities that allow them to exist in more than one place at the same time—until you take a look and check up on them. this fragile state, in which the particle can possess multiple contradictory attributes, is called a superposition. according to the standard view of quantum mechanics, measuring a particle’s properties is a violent process that instantly snaps the particle out of superposition and collapses it into a single identity. why and how this happens is one of the central mysteries of quantum mechanics.
09-03-2010, 03:04 AM
The Extraordinary Tale of Red Rain, Comets and Extraterrestrials
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the extraordinary tale of red rain, comets and extraterrestrials
for years, claims have circulated that red rain which fell in india in 2001, contained cells unlike any found on earth. now new evidence that these cells can reproduce is about to set the debate alive
panspermia is the idea that life exists throughout the universe in comets, asteroids and interstellar dust clouds and that life of earth was seeded from one or more of these sources. panspermia holds that we are all extraterrestrials.
while this is certainly not a mainstream idea in science, a growing body of evidence suggests that it should be carefully studied rather than casually disregarded.
for example, various bugs have been shown to survive for months or even years in the harsh conditions of space. and one of the more interesting but lesser known facts about the mars meteorite that some scientists believe holds evidence of life on mars, is that its interior never rose above 50 degrees centigrade, despite being blasted from the martian surface by an meteor impact and surviving a fiery a descent through earth's thick atmosphere.
if there is life up there, this evidence suggests that it could survive the trip to earth.
[moderator: although this is a blog, the individual is reporting a scientific study without opinion,, which does qualify it for consideration on our forum]
09-07-2010, 07:04 AM
the geometry of space
have you ever wondered what this reality is made of? this atomic structure that is palpable, that seems so real? how is it that from nothingness everything emerges? atoms are made of
99.99999% space, so it turns out that what we call reality is mostly space with a little bit of a
jiggle—a little vibratory fluctuation or, as described in quantum theory, a waveform generating
what we call atomic structure. one must wonder, couldn't this fluctuation be a function of the
space itself? could space actually be full instead of empty? couldn't atomic structures be only the symptom of the fluctuation of space?...
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