Scientists from the University of Michigan used a laser to produce a quantum state in a qubit, at a frequency of gigahertz, or a billion times per second. They can also use lasers to take basic steps towards programming
The quantum computer The fastest showing the advantages of the qubit (quantum bit) over the normal bit, was presented by researchers from the University of Michigan, USA, the Naval Research Laboratories and the University of California at San Diego.
Scientists used a laser to produce a quantum state in a qubit, at a frequency of gigahertz, or a million times per second. They can also use lasers to take basic steps towards programming.
Everything you wanted to know about quantum computing
A conventional bit can be either 0 or 1. A quantum bit, or qubit, can be both at the same time. To date scientists have not been able to produce this dual state stably.
Physicist Professor Duncan Steel, PhD student Xiaodong Xu and their colleagues used lasers to coherently and stably capture the spin of a semiconductor electron in a quantum dot state. A quantum dot is likened to a transistor in a conventional computer.
The scientists captured the spin in a dark state where the qubit was arbitrarily tuned to 0 and 1. They call this state "dark state" because it does not reflect light. That is, light does not cause the loss of coherence between the two modes. The light does not destabilize the qubit. A study regarding these findings will be published in the journal Nature Physics.
"We are the first to show that this can be done on a single electron converging to a quantum dot state," says Steele. "If you're going to do quantum programming, you have to be able to work on a single electron at a time."
Spin is an intrinsic property of an electron that is not true rotation. Steele likens it to magnetic poles. Electrons have up or down spins. In quantum computing, up and down directions are represented by 0 or 1 as in conventional computing.
Steele's approach to developing quantum computers is to use superfast lasers to control arrays of semiconductor quantum dots, each containing a single electron. Quantum logic gates are created by quantum interactions between the dots.
Previously in Steele's lab, researchers used a laser to produce an electron in one of the 1 or 0 states and some of the other state. Now using two different laser frequencies, they have trapped the spin in the 0 and 1 state at the same time, and they can control the amount of each.
Because the electron is trapped inside the dark state, light directed at it cannot destroy the coherence. Energy from the light can reverse the spin of the electron, or qubit, and mess up the information stored on the bit.
"This dark state is a place where the information can be stored without any errors," says Steele.
Thanks to their ability to represent multiple states simultaneously, quantum computers can dramatically reduce computation time compared to conventional computers. Therefore, they have great potential in improving computer security.
"The national security system in the US said that based on the existing technology, we have a security window of 20 years," says Steele. "That means if we send a satellite today, it will take 20 years to crack its code. Quantum computers will make it possible to develop a code that is unbreakable using a conventional computer."
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Ofer Levinger:
Read here
http://en.wikipedia.org/wiki/Quantum_computing
Peace.
It sounds like such a quantum computer will do logical operations of a normal computer only in a shorter time
and not on the principle of superposition.
Even if a quantum computer would work a billion times faster than it does today, adding 100 bits to the RSA algorithm would increase the time needed to solve it by many times.
It is really not clear how to find divisors of a large number (it seems to me that this is the first problem that needs to be addressed because every program is capable of programming RSA that the universe will collapse until the NSA deciphers it without a quantum computer) - how to make a series of electrons in superposition become a possible divisor of another number that is represented By a sequence of electrons, the electrons themselves do not know where they are and what digit they represent. In my opinion, any such task requires a specific algorithm that will tell the electrons what they are supposed to find, and not a sequence of logical operations in a certain order, and that is why the difficulty.
More about quants can be found in "Secrets of Cryptography"
Higgs
What is strange is that suddenly, in a sudden light, a quantum jumped to me for a fraction of a second, and I understood...
One of the..all...(until the next station..)
This is all really confusing but…..
Each measurable state on the particle scale is what is called a quantum collapse of a wave state defined as a superposition. This is the wave equation that describes the collection of all possible states of the particle.
This collection includes all the measurements in all the different aspects.
Take for example Rohm, his wave function describes the envelopes he counted at the same time and all the flights to all destinations at the expense of each and every one of the donors, etc. and all this at the same time which is certainly impressive. That is, it makes it possible to shrink the entire history consisting of discrete events into a single wave that contains them all together.
Usually the collapse of the wave gives only one value and one measure for the collection of characteristics, however if we can reverse the direction ie cause two-way symmetry in such a way that the collapse is not one-sided. The result is as if your pocket calculator calculates the entire sequential series of calculations of the last grocery bill at the same time. Suppose there are 100 items in the list, the calculation is done as if at once. It's a bit confusing, but even the Hessicians don't really understand it, so it's not bad.
Does this mean that it will soon be impossible to decipher messages encrypted by this type of computer?
A friend?? And a secret, and of course!
Just so you know, that at this moment my "single electron" lost its magnetic "north" with
The rotation of the "spin", which is not exactly a rotation, the quantum connection, for the whole thing, has been relegated to some niche...maybe
Just our point, I understand what it's about. The megabits.. got lost in some megalomaniacal computer,
that I don't understand a thing about it...and the wonder of it, that despite this I still continue to follow and understand
At this moment, hide from my eyes.
Apparently, another article took me down, temporarily, Shawla. Sorry.
Gentlemen will teach me.
The spin states are not continuous but discrete, so what does it say that the amount of spin can be controlled? On the other hand, it is also written that the electron can be in the dark state, meaning both, but at different levels?
And to conclude - does the speed and security of quantum computing result from the fast switching or from the fact that there is another state - dark (and again - are there more states?) on the zero and the one?
Roy: Corrected in the bolded summary, it appears again in the sixth line.
Thanks, corrected.
And to the point: the reason the field progresses so slowly is
that while a quantum computer has "exponential" computing power in the number of qubits, there is also exponential difficulty in building a computer with such a number of qubits.
In other words: there are no free meals.
There is an error in the article "gigahertz, or a million times per second"
Giga = billion
Mega = million
Why is this field moving so slowly?