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To use this gate, Kumar needs photons that are identical in every way except polarization, or the orientation of their electromagnetic fields.These "identical" photons are sent through optical fiber to the gate itself, a small maze of devices that route photons in different directions depending on their polarization. Passing through the maze causes certain photon pairs to become entangled. But not all photons make it through the gate; only when photons reach detectors on the other end, and the researchers can measure whether or not they are entangled, do they know the gate succeeded.
The only way to know whether or not the gate worked is to wait until a collection of photons has been fired at it, says Carl Williams, coordinator of the quantum information program at the National Institute of Standards and Technology. "Most of the time the gate fails," he says. "It's a probabilistic thing." But when the gate fails, the researchers simply disregard the unentangled photons.
"The great thing about this work," says Williams, "is that it's in fiber. This is a big deal because it could lead to distributed networks. ... The obvious application is for long-distance quantum communication between two smaller quantum computers." One of the crucial elements in a conventional optical network is a device called a repeater, which amplifies signals that have degraded over distance. Williams says that a quantum logic gate, such as the one that Kumar built, could be used in a circuit that amplifies a signal without losing the entanglement of the photons.
"This is an important step toward constructing a quantum Internet," says Seth Lloyd, a professor of mechanical engineering at MIT and a leading researcher in quantum computation. "Such a network would have powers that the ordinary Internet does not," he says. "In particular, communication over the quantum Internet would be automatically secure."
Lloyd notes that Kumar's paper illustrates how a simple quantum logic operation can be performed using individual photons. "The current paper represents a significant advance in the technology of quantum computation and quantum networks," he says.
Defense contractor Lockheed Martin paid $10 million for a "quantum computer" that is also being tested by Google.
Researchers at IBM now know how long a single atom can "remember" its state.
Researchers suggest an optical processing method that could lead to faster telecommunications.
No no, the end result of the gate would have to be 100% entangled, I would imagine for total security in the environment. And the X^2 binary we know would double, becase the quibit it both a "1" and "0" at the same time. So it would be x^4
I don't know much about quantum computation. However the article says that quantum computers can deal with exponentially more information than classical computers. x^2, x^3, x^4 are all polynomials. Exponential implies something of the form a^x, with constant a.
Yeah, I think the original poster probably meant the 2^x binary we know, since the number of possible values that can be expressed by x bits is 2^x. So x qubits can express all those values simultaneously; a calculation performed using eight qubits, for instance, is the equivalent of 256 separate calculations on a classical computer.
http://www.cs.caltech.edu/~westside/quantum-intro.html
This article really helped me wrap my head around the basics of quantum computers. And this article is just a bit more challenging but provides a great basis:
http://antoine.frostburg.edu/chem/senese/101/quantum/
Enjoy :)
Indeed, quantum computers will be affecting our lives directly, even though they rely on quantum phenomena, so it's much easier to understand what's going on in that weird world.
This article defines qubit just a bit inaccurately. A qubit is 1, 0, and a superposition between 1 and 0. So it isn't that it is 1 and 0 at the same time, it embodies all values between as well. At least, from my reading, that is how I understand it.
This just in ... Comcast researchers discover a way to increase rates on a quantum level by acting as internet gate keepers. Comcast calls this the "Quantum Net", and promises to charge every website a toll per visitor, thus Quantumly enhancing their profits and decreasing user satisfaction simultaneously.
Wow!, some progress ... finally. This article does give hope that I'll someday have some kind of Apple computer device in my arthritic hands for my Alzheimered mind to play with before I croak. Though I suppose I'll probably be long gone dead when the throw the switch to turn on the first commercial fusion engine. I mean, talk about snail's pace.
When was the word quantum first uttered in relation to the atomic world? More than eighty years ago?
Geez, let's get going, fellas! God forbid some Bangladeshi, or heavens to Mergatroid, a North Korean brilliantly writes the paper of Papers ...! The humiliation we'll pass on to future generations, and it'll never lie down.
Don't worry too much, we've got them all working in our research labs already, so we can just take the credit when they find something.
Unfortunately, quantum computing is one of the areas I've started to allow other people to learn about instead of taking it on myself. I may be able to wrap my head around it all with enough effort but I'm beginning to realize how little impact I have on the subject compared with other areas. The amount of effort it takes to become an expert in this particular field is better left to someone more passionate about it than myself. It's basically become the next subject ignored in a line that started with Greek Tragedy.
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This document is part of the “How-To Guide for Most Common Measurements” centralized resource portal. This tutorial provides a detailed guide for measurement and device considerations to take temperature measurements using thermocouples. Get an introduction to thermocouples, which are inexpensive sensing devices widely used with PC-based data acquisition systems. Also review some specific thermocouple examples and learn how thermocouples work and ways to integrate them into a data acquisition measurement system.
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Shiladie
56 Comments
Reliability
I'm assuming that the chance of the photons not being entangled would have to be lowered before this can be put into a production environment.
also, with the qubit, is it simply taking the X^2 of binary we know and love and making it X^3 by adding a 3rd option? or is there more that I'm not understanding?
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brunascle
65 Comments
Re: Reliability
with the qubit, is it simply taking the X^2 of binary we know and love and making it X^3 by adding a 3rd option?
not really. from what i understand, a qubit is kind of like a bunch of regular bits blurred together. each of those bits can only be a 1 or 0.
and a quantum computer is kind of like a bunch of classical (binary) computers blurred together, all running the same algorithm at the same time. each one comes up with a different answer, and if the algorithm is set up right, the one answer you're looking for will stand out above the rest.
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