Thursday, 6 June 2013

The First Image Ever of a Hydrogen Atom's Orbital Structure






You’re looking at is the first direct look of an atom’s electron orbits which can be mathematically described by Atom's Real wave function! To take the photo, Scientists utilized A quantum microscope — an incredibly Innovative device that helps scientists to look into the quantum world.!

An orbital structure is the space in an atom that’s occupied by an electron. But describing these super-microscopic properties of matter, scientists have to depend on wave functions — a mathematical way of describing the quantum states of particles,  basically, quantum physicists use formulas like the Schrödinger equation to describe these states, often coming up with complex numbers and Strange graphs!

Up until this point, scientists have never been able to actually observe the electron orbit. Trying to get an atom’s exact position or the momentum of its alone electron direct observations have this obstacle of  quantum coherence. So to get a full quantum state We need tool that can statistically average many measurements over time And to magnify this results scientists needs the quantum microscope — a device that uses photoionization microscopy to visualize atomic structures directly.

Aneta Stodolna of the FOM Institute for Atomic and Molecular Physics (AMOLF) in the Netherlands describes how she and her team get a picture of the nodal structure of an electronic orbital of a hydrogen atom placed in a static (dc) electric field in Physical Reviw Letter..


The First Image Ever of a Hydrogen Atom's Orbital Structure


After zapping the atom with laser pulses, ionized electrons escaped and followed a particular trajectory to a 2D detector (dual microchannel plate [MCP] detector placed perpendicular to the field itself). There are many trajectories that can be taken by the electrons to reach the same point on the detector, thus Scientist got the set of interference patterns — patterns that shows the nodal structure of the wave function.

And the they have done this by using an electrostatic lens that magnified the outgoing electron wave more than 20,000 times.



Image: Examples of four atomic hydrogen states. The middle column shows the experimental measurements, while the column at right shows the time-dependent Schrödinger equation calculations.



Quantum Link Between Photons That Don't Exist at the Same Time

Physicists have long known that quantum mechanics tells a strange connection between quantum particles "Entanglement" In which measuring one particle can instantly set "state," of another particle—even if it's light years away. Now, experiments have shown that they can entangle two photons that don't even exist at the same time even.....!!!




Entanglement is a kind of order that leis within the uncertainty of quantum theory. Suppose you have a quantum particle of light, or photon. It can be polarized so that it either vertically or horizontally. The quantum realm is also hazed over with unavoidable uncertainty, and thanks to such quantum uncertainty, a photon can also be polarized vertically and horizontally at the same time. If you then measure the photon, however, you will find it either horizontally polarized or vertically polarized,




Entanglement can come in if you have two photons. Each can be put into the uncertain vertical-and-horizontal state. However, the photons can be entangled so that their polarizations are correlated even while they remain undetermined. For example, if you measure the first photon and find it horizontally polarized, you'll know that the other photon has instantaneously collapsed into the vertical state and vice versa—no matter how far away it is. Because the collapse happens instantly, Albert Einstein dubbed the effect "spooky action at a distance." It doesn't violate relativity, though: It's impossible to control the outcome of the measurement of the first photon, so the quantum link can't be used to send a message faster than light.
Now Eli Megidish, Hagai Eisenberg, and colleagues at the Hebrew University of Jerusalem have entangled two photons that don't exist at the same time. They start with a scheme known as entanglement swapping. To begin, researchers zap a special crystal with laser light a couple of times to create two entangled pairs of photons, pair 1 and 2 and pair 3 and 4. At the start, photons 1 and 4 are not tangled. But they can be if physicists play the right trick with 2 and 3.

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The key is that a measurement "projects" a particle into a definite state -- just as the measurement of a photon collapses it into either vertical or horizontal polarization. So even though photons 2 and 3 start out unentangled, physicists can set up a "projective measurement" that asks, are the two in one of two distinct entangled states or the other? That measurement entangles the photons, even as it absorbs and destroys them. If the researchers select only the events in which photons 2 and 3 end up in, say, the first entangled state, then the measurement also entangles photons 1 and 4. (See diagram, top.) The effect is a bit like joining two pairs of gears to form a four-gear chain: Enmeshing to inner two gears establishes a link between the outer two.
In recent years, physicists have played with the timing in the scheme. For example, last year a team showed that entanglement swapping still works even if they make the projective measurement after they've already measured the polarizations of photons 1 and 4. Now, Eisenberg and colleagues have shown thatphotons 1 and 4 don't even have to exist at the same time, as they report in a paper in press at Physical Review Letters.
To do that, they first create entangled pair 1 and 2 and measure the polarization of 1 right away. Only after that do they create entangled pair 3 and 4 and perform the key projective measurement. Finally, they measure the polarization of photon 4. And even though photons 1 and 4 never coexist, the measurements show that their polarizations still end up entangled. Eisenberg emphasizes that even though in relativity, time measured differently by observers traveling at different speeds, no observer would ever see the two photons as coexisting.
The experiment shows that it's not strictly logical to think of entanglement as a tangible physical property, Eisenberg says. "There is no moment in time in which the two photons coexist," he says, "so you cannot say that the system is entangled at this or that moment." Yet, the phenomenon definitely exists. Anton Zeilinger, a physicist at the University of Vienna, agrees that the experiment demonstrates just how slippery the concepts of quantum mechanics are. "It's really neat because it shows more or less that quantum events are outside our everyday notions of space and time."
So what's the advance good for? Physicists hope to create quantum networks in which protocols like entanglement swapping are used to create quantum links among distant users and transmit uncrackable (but slower than light) secret communications. The new result suggests that when sharing entangled pairs of photons on such a network, a user wouldn't have to wait to see what happens to the photons sent down the line before manipulating the ones kept behind, Eisenberg says. Zeilinger says the result might have other unexpected uses: "This sort of thing opens up people's minds and suddenly somebody has an idea to use it in quantum computing or something."

Jenish

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New Delhi, New Delhi, India
is a Cisco Certified Internetworking Expert. He is working in the domain of Routing & switching also working with Next Generation Networks implementation. Apart from that he is actively involved in String Theory Development and Quantum Physics research.