Quantum computers are largely hypothetical devices that could perform some calculations much more rapidly than conventional computers can. Instead of the bits of classical computation, which can represent 0 or 1, quantum computers consist of quantum bits, or qubits, which can, in some sense, represent 0 and 1 simultaneously.
Although quantum systems with as many as 12 qubits have been demonstrated in the lab, building quantum computers complex enough to perform useful computations will require miniaturizing qubit technology, much the way the miniaturization of transistors enabled modern computers.
Trapped ions are probably the most widely studied qubit technology, but they’ve historically required a large and complex hardware apparatus. In today’s Nature Nanotechnology, researchers from MIT and MIT Lincoln Laboratory report an important step toward practical quantum computers, with a paper describing a prototype chip that can trap ions in an electric field and, with built-in optics, direct laser light toward each of them.
A standard ion trap looks like a tiny cage, whose bars are electrodes that produce an electric field. Ions line up in the center of the cage, parallel to the bars. A surface trap, by contrast, is a chip with electrodes embedded in its surface. The ions hover 50 micrometers above the electrodes.
“We believe that surface traps are a key technology to enable these systems to scale to the very large number of ions that will be required for large-scale quantum computing,” says Jeremy Sage, who together with John Chiaverini leads Lincoln Laboratory’s trapped-ion quantum-information-processing project. “These cage traps work very well, but they really only work for maybe 10 to 20 ions, and they basically max out around there.”
Performing a quantum computation, however, requires precisely controlling the energy state of every qubit independently, and trapped-ion qubits are controlled with laser beams. In a surface trap, the ions are only about 5 micrometers apart. Hitting a single ion with an external laser, without affecting its neighbors, is incredibly difficult; only a few groups had previously attempted it, and their techniques weren’t practical for large-scale systems.
The Moscow Institute of Physics and Technology (MIPT) is probing cutting edge diamond technologies to emit single photons (for uncrackable cybersecurity) and graphene to detect single molecules (for pathogen early detection). While experts around the world are also addressing these angstrom (one-tenth of a nanometer) scale problems, few laboratories are making headway in both.
Dmitry Fedyanin, a researcher from MIPT’s Laboratory of Nano-optics and Plasmonics together with his Italian colleague Mario Agio from the University of Siegen (Germany), may have cracked the most vexing problem in uncrackable quantum encryption. By using diamonds as high-speed emitters of single angstrom-scale quantum encoded photons they may have opened the door to high-intensity (that is high-speed of 100-MHz) quantum key communications.
Qubit device fabbed in standard CMOS
In a major step toward commercialization of quantum computing, Leti, an institute of CEA Tech, along with Inac, a fundamental research division of CEA, and the University of Grenoble Alpes have achieved the first demonstration of a quantum-dot-based spin qubit using a device fabricated on a 300-mm CMOS fab line.
Maud Vinet, Leti’s advanced CMOS manager said, “This proof-of-concept result, obtained using a CMOS fab line, is driving a lot of interest from our semiconductor industrial partners, as it represents an opportunity to extend the impact of Si CMOS technology and infrastructure beyond the end of Moore’s Law.”
The proof-of-concept breakthrough uses a device fabricated on a 300-mm CMOS fab line consisting of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot encoding a hole spin qubit, and the second one defines a quantum dot used for the qubit readout. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate, the team explained.
The one-qubit demonstrator brings CMOS technology closer to the emerging field of quantum spintronics.
Vinet added: “This proof-of-concept result, obtained using a CMOS fab line, is driving a lot of interest from our semiconductor industrial partners, as it represents an opportunity to extend the impact of Si CMOS technology and infrastructure beyond the end of Moore’s Law. The way toward the quantum computer is still long, but CEA is leveraging its background in physics and computing, from technology to system and architecture, to build a roadmap toward the quantum calculator.”
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3 Comments
Tomi Engdahl says:
Toward practical quantum computers
Built-in optics could enable chips that use trapped ions as quantum bits
http://news.mit.edu/2016/toward-practical-quantum-computers-0808
Quantum computers are largely hypothetical devices that could perform some calculations much more rapidly than conventional computers can. Instead of the bits of classical computation, which can represent 0 or 1, quantum computers consist of quantum bits, or qubits, which can, in some sense, represent 0 and 1 simultaneously.
Although quantum systems with as many as 12 qubits have been demonstrated in the lab, building quantum computers complex enough to perform useful computations will require miniaturizing qubit technology, much the way the miniaturization of transistors enabled modern computers.
Trapped ions are probably the most widely studied qubit technology, but they’ve historically required a large and complex hardware apparatus. In today’s Nature Nanotechnology, researchers from MIT and MIT Lincoln Laboratory report an important step toward practical quantum computers, with a paper describing a prototype chip that can trap ions in an electric field and, with built-in optics, direct laser light toward each of them.
A standard ion trap looks like a tiny cage, whose bars are electrodes that produce an electric field. Ions line up in the center of the cage, parallel to the bars. A surface trap, by contrast, is a chip with electrodes embedded in its surface. The ions hover 50 micrometers above the electrodes.
“We believe that surface traps are a key technology to enable these systems to scale to the very large number of ions that will be required for large-scale quantum computing,” says Jeremy Sage, who together with John Chiaverini leads Lincoln Laboratory’s trapped-ion quantum-information-processing project. “These cage traps work very well, but they really only work for maybe 10 to 20 ions, and they basically max out around there.”
Performing a quantum computation, however, requires precisely controlling the energy state of every qubit independently, and trapped-ion qubits are controlled with laser beams. In a surface trap, the ions are only about 5 micrometers apart. Hitting a single ion with an external laser, without affecting its neighbors, is incredibly difficult; only a few groups had previously attempted it, and their techniques weren’t practical for large-scale systems.
Tomi Engdahl says:
Advances Get a Grip on Single Photons & Molecules
Single molecules & photons can be detected, emitted
http://www.eetimes.com/document.asp?doc_id=1330340&
The Moscow Institute of Physics and Technology (MIPT) is probing cutting edge diamond technologies to emit single photons (for uncrackable cybersecurity) and graphene to detect single molecules (for pathogen early detection). While experts around the world are also addressing these angstrom (one-tenth of a nanometer) scale problems, few laboratories are making headway in both.
Dmitry Fedyanin, a researcher from MIPT’s Laboratory of Nano-optics and Plasmonics together with his Italian colleague Mario Agio from the University of Siegen (Germany), may have cracked the most vexing problem in uncrackable quantum encryption. By using diamonds as high-speed emitters of single angstrom-scale quantum encoded photons they may have opened the door to high-intensity (that is high-speed of 100-MHz) quantum key communications.
Tomi Engdahl says:
System Bits: Nov. 29
300mm quantum demo
http://semiengineering.com/system-bits-nov-29/
Qubit device fabbed in standard CMOS
In a major step toward commercialization of quantum computing, Leti, an institute of CEA Tech, along with Inac, a fundamental research division of CEA, and the University of Grenoble Alpes have achieved the first demonstration of a quantum-dot-based spin qubit using a device fabricated on a 300-mm CMOS fab line.
Maud Vinet, Leti’s advanced CMOS manager said, “This proof-of-concept result, obtained using a CMOS fab line, is driving a lot of interest from our semiconductor industrial partners, as it represents an opportunity to extend the impact of Si CMOS technology and infrastructure beyond the end of Moore’s Law.”
The proof-of-concept breakthrough uses a device fabricated on a 300-mm CMOS fab line consisting of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot encoding a hole spin qubit, and the second one defines a quantum dot used for the qubit readout. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate, the team explained.
The one-qubit demonstrator brings CMOS technology closer to the emerging field of quantum spintronics.
Vinet added: “This proof-of-concept result, obtained using a CMOS fab line, is driving a lot of interest from our semiconductor industrial partners, as it represents an opportunity to extend the impact of Si CMOS technology and infrastructure beyond the end of Moore’s Law. The way toward the quantum computer is still long, but CEA is leveraging its background in physics and computing, from technology to system and architecture, to build a roadmap toward the quantum calculator.”
A CMOS silicon spin qubit
http://www.nature.com/articles/ncomms13575