A quantum computer is a far more quickly than traditional computer, some calculation unfulfilled equipment. Calculation of quantum computing and classic representation of 0 or 1 in a different way of calculating the quantum computer consists of qubits (qubit), qubits can 0 and 1 at the same time.
Although quantum systems with up to 12 qubits have been confirmed in the laboratory, but create enough complex calculation of quantum computers can perform valuable need to miniaturization of qubits technology, it's like the miniaturization of transistors with the modern computer.
Trapped ion (trapped ions) is the most widely studied by quantum bits of technology, but they always need to be large and complex in history of hardware. In today's Nature Nanotechnology, MIT and the MIT Lincoln laboratory researchers published a paper called and took an important step toward practical quantum computer, the paper describes a new type of prototype chip, the chip can be ions trapped in an electric field, and use the built-in laser guided optical device to each ion.
"If you look at the traditional assembly method, it is an internal vacuum barrels, inside is the" cage "used to detain ion. Then basically requires an entire lab external optical equipment for laser beam will lead to ion on the assembly of." One of the paper's senior author, MIT professor of electrical engineering, Rajeev Ram said, "our vision is to put the whole external laboratory miniaturization on a chip."
Into the cage
Lincoln laboratory of the Quantum Information and integration of nanoscale systems group (Quantum Information and Integrated Nanosystems) are a few of the so-called development more simple small trap "surface (surface traps)," one of the research team. A standard of ion trap (ion trap) looks like a small cage, but it is fence can generate electric field of the electrode. Ion in the cage, in the middle of the parallel to the fence. The surface trap is electrodes embedded in the surface of the chip. Its ion suspended in the electrode height above 50 microns.
Cage trap the essence of the size limitation, but the surface trap in theory can be extended indefinitely. Under the current technical level, they still need to be placed in a vacuum chamber, but they can be allowed in the inner configuration much more qubits.
"We believe that in order to bring the system of large-scale quantum computing need a very large number of ions on the surface of the trap is a key technology. The cage trap effect is very good, but they can only work on 10 or 20 ions, to that level is nearly/almost the biggest." Jeremy Sage said, he led Lincoln laboratory with John Chiaverini trapped ion quantum information processing projects (trapped ion quantum - information - processing project).
While performing quantum computing need is independent for each qubit is accurate energy state (energy state) control. Trapped ion qubit used to control the laser beam. In a surface trap, the distance between the ions only 5 microns. Using external laser shooting near an ion and sometimes will not affect its ion is very difficult; Only a few research team tried to do this, but their technology does not apply to large-scale systems.
Integrated into the plate
This is the Ram's team do. Ram and Karan Mehta (MIT electrical engineering graduate student, the first author of this paper) is designed and established a piece can lead to a single ion laser optical components. Sage, Chiaverini and their colleagues Lincoln laboratory Colin Bruzewicz and Robert McConnell, to improve their surface traps, can make it under the condition of not detract from the performance of the adaptive integrated optics. Together, the two team to design and perform the experiment, to test the new system.
Ram said, "for surface electrode trap, laser beam from an optical table (optical table) and enter the system, so we always worry about beam vibration or movement. A photonic integration (photonic integration), you don't need to worry about the stability of the light, because they are on the same electrode chip. So everything is fixed to one another, it is stable."
A quantum computer is a far more quickly than traditional computer, some calculation unfulfilled equipment. Calculation of quantum computing and classic representation of 0 or 1 in a different way of calculating the quantum computer consists of qubits (qubit), qubits can 0 and 1 at the same time.
The new chip based on Shi Yingji board. At the top of the quartz is a silicon nitride "guided wave tube (waveguide)" network, can guide the laser on a chip. Guided wave tube top is a glass layer, the top is a niobium electrode. Down to the bottom of the hole in the electrode, guided wave tube is decomposed into a series of continuous convex ridge (ridges), a precise design "diffraction grating" led light through the holes, and focus on a narrow beam of light enough to target a single ion, it is more than 50 microns on the surface of the chip.
vision
Using this prototype chips, the researchers assessed the diffraction grating and the performance of the ion trap, but there is no mechanism to be able to communicate to each ion change the number of photons. In the next work, these researchers will join in the diffraction grating light modulator, so that the qubits can receive different photons, intensity changes over time. This work will be made more efficient programming qubits, the quantum information in practical system is very important, because the system can perform quantum operation by the number of qubits "coherence time (coherence time)".
"As far as I know, this is on the same chip as the first attempt to ion trap integrated optical waveguide. This is also expanding of ion trap quantum information processor (QIP) into final contains enough useful for quantum information processing is an important step in the number of quantum bits." A physics professor at the university of Oxford, David Lucas says, "it is well known that the trapped ion qubit can achieve record coherence time, and on a small number of qubits can be very precise operation. But it is worth arguing about, in order to realize the system extended to larger Numbers of qubits technology, which is the most important in the field of which process need to do. That's what this research is trying to solve demand."
Lucas added: "of course, recognizing this is just the beginning of presentation is also very important. But to believe that this technology can gain significant improvements, it is very promising. As a first step, it is a very good results."
