Quantum Processors for Single Photons

Scientists have realized a photon-photon logic gate via a deterministic interaction with a strongly coupled atom-resonator system.

A team of scientists from the Quantum Dynamics Division of Professor Gerhard Rempe has successfully realized a quantum logic gate where two light quanta play the key actors. Professor Gerhard Rempe is the director at the Max Planck Institute of Quantum Optics. This attempt was highly challenging as photons do not typically interact at all but pass each other uninterrupted


Illustration of the processes that take place during the logic gate operation: The photons (blue) successively impinge on the right onto the partially transparent mirror of a resonator which contains a single rubidium atom (symbolized by a red sphere with yellow electron orbitals). The atom in the resonator plays the role of a mediator which imparts a deterministic interaction between the two photons. The diagram in the background represents the entire gate protocol. Credit: Graphic: Stephan Welte, MPQ, Quantum Dynamics Division

In the experiment presented here two independently polarized photons impinge, in quick succession, onto a resonator which is made of two high-reflectivity mirrors. Inside a single rubidium, an atom is trapped forming a strongly coupled system with the resonator. The resonator amplifies the light field of the impinging photon at the position of the atom enabling a direct atom-photon interaction. As a result, the atomic state gets manipulated by the photon just as it is being reflected from the mirror. This change is sensed by the second photon when it arrives at the mirror shortly thereafter.


After their reflection, both photons are stored in a 1.2-kilometre-long optical fiber for some microseconds. Meanwhile, the atomic state is measured. A rotation of the first photon’s polarization conditioned on the outcome of the measurement enables the back action of the second photon on the first one. “The two photons are never at the same place at the same time and thus they do not see each other directly. Nevertheless, we achieve a maximal interaction between them,” explains Bastian Hacker, a Ph.D. student at the experiment.

The scientists envision that the new photon-photon gate could pave the way towards all-optical quantum information processing. “The distribution of photons via an optical quantum network would allow linking any number of network nodes and thus enable the setup of a scalable optical quantum computer in which the photon-photon gate plays the role of a central processing unit (CPU),” explains Professor Gerhard Rempe.



via: ScienceDaily

Intel’s 1st 10-Core Desktop CPU

Intel announced a new family of high-end desktop processors code-named Broadwell-E which packs 10 Broadwell CPU cores. This 10-cores are marketed as a part of the Core i7 6950x. The previous generation Haswell-E had 8 cores.

The prior-generation Haswell-E processor family was formed on a single chip: the eight-core Haswell-EP server processor. In its full configuration, it was sold as the $999 Core i7 5960X, with six-core variants made out of cut-down versions of that same chip.

That die measured in at 356 square millimeters in Intel’s 22-nanometer manufacturing process.



The 10-core Broadwell-E chip is simply the full 10-core Broadwell-EP server chip relabeled and repurposed as a high-end desktop processor. The eight-core model, as well as the two six-core models, are also fashioned out of this same processor.

The size of the die is approximately 246 square millimeters, or approximately 69% the size of the Haswell-E die that it replaces.

Intel claims that it’s twice as fast as the quad-core i7-6700k and 35% faster than the previous gen core i7-5960k. Editing 4k video will be 65% faster than the same quad-core chip and 25% faster than previous gen i7 processor. Gaming is 25 percent faster than the 5960X when it comes to gaming in 4K while encoding and broadcasting a 1080p Twitch stream.



Intel has indicated in the past that the wafer cost increase, or effectively the cost per area of silicon, was approximately 30% in going from 22-nanometer to 14-nanometer. This means that all else equal, 246 square millimeters of 14-nanometer silicon should cost about the same as approximately 320 square millimeters of 22-nanometer silicon.

Right off the bat, it would seem that the 10-core Broadwell-E is actually cheaper to manufacture relative to the eight-core Haswell-E.

However, it’s important to note that Intel saw a decline in the gross profit margins of its data center business as a result of 14-nanometer yields relative to 22-nanometer yields.

  1. Broadwell-E: 246 square millimeter die, the defect density of 0.2 defects/square centimeter, $9,100 wafer cost.
  2. Haswell-E: 356 square millimeter die, the defect density of 0.1 defects/square centimeter, $7,000 wafer cost.

For the Broadwell-E part, under the above assumptions, 139 of the 223 dies that come off the wafer are good. For the Haswell-E part, of the 153 dies on the wafer, 109 come out good.

Based on this analysis, the raw die cost of the 14-nanometer part should be around $83. The cost of the 22-nanometer part under these assumptions works out to around $64.

The new Extreme Edition of i7 processors will also be available in an 8-core version (the i7-6900K for $1,089) and 6-core variants (the $617 i7-6850K and the $434 i7-6800K). Naturally, they’re completely unlocked, so you can overclock them to your heart’s content. All of the new chips also support DDR4-2400 RAM, a slight bump in speeds from the previous-gen processors. Intel is charging around $1,750 for the 6950X, compared to around $1,000 for the 5960X.


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(sources: Engadget, Fool)