At the IEEE Industry Summit on the Future of Computing in Washington D.C. in Oct 2017, IBM announced the development of a quantum computer capable of handling 50 qubits (quantum bits) so far the largest and most powerful quantum computer ever built.
Unlike digital computer which understands only a bit that can have only one of two values: “1” or “0,” qubits have special property termed superposition, which can simultaneously be a 0 and/or a 1. This enables quantum computers to weed through millions of solutions all at once, while desktop PCs would have to consider them one at a time. The team recently demonstrated the first experimental realization of parity check with three superconducting qubits, an essential building block for one type of quantum computer.
With this IBM has taken a big step in its plans to scale their quantum computer between 50 and 100 qubits within the next decade towards building a universal quantum computer. A universal quantum computer can be programmed to perform any computing task and will be exponentially faster than classical computers for a number of important applications for science and business.
IBM had planned a massive $3 billion research and development investment over the next 5 years into quantum computers, post-silicon era chips, neurosynaptic computers which mimic the behavior of living brains, carbon nanotubes, graphene tools and a variety of other technologies. IBM’s investment is one of the largest for quantum computing to date.
Aside from their 50-qubit machine, IBM also has a 20-qubit quantum computing system that’s accessible to third-party users through their cloud computing platform. IBM managed to maintain the quantum state for both systems for a total of 90 microseconds, a record feat in the quantum world.
IBM announced earlier that the U.S. Intelligence Advanced Research Projects Activity (IARPA) program has notified IBM that it will award its scientists a major multi-year research grant to advance the building blocks for a universal quantum computer. The spy agencies are now giving thrust to development of Quantum computers which can break this encryption used by terrorists.
Encrypted communications used by terrorists has become very difficult to crack
The investigation into coordinated terrorist attacks in France has quickly turned up evidence that members of the Islamic State (ISIS) communicated with the attackers from Syria using encrypted communications, according to French officials.
Al Qaeda has used various forms of encryption to hide files on websites for dissemination, as well as using encrypted or obfuscated files carried on CDs or USB drives by couriers. The organization has heavily used steganography to conceal electronic documents—even files within pornographic videos on websites—rather than relying on e-mail, and has used the technique since before the September 11, 2001 attacks.
Former CIA Deputy Director Michael Morell said in an interview on CBS’, “I think what we’re going to learn is that these guys are communicating via these encrypted apps, this commercial encryption which is very difficult or nearly impossible for governments to break, and the producers of which don’t produce the keys necessary for law enforcement to read the encrypted messages.”
Current public key cryptology can be easily broken by quantum Computers
Modern cryptography being used extensively for securing our internet payments, banking transactions, emails and even phone conversations use cryptographic algorithms based on public-key encryption, which is considered to be secure against attacks from modern computers.
By harnessing quantum super-positioning to represent multiple states simultaneously, quantum-based computers promise exponential leaps in performance over today’s traditional computers. Quantum algorithms can break current security by reverse computing private keys faster than a conventional computer.
The development of quantum computers once seen as a remote theoretical possibility is now advancing rapidly and expected to enter mainstream within a decade. Quantum computers shall bring power of massive parallel computing i.e. equivalent of supercomputer to a single chip. They shall also be invaluable in cryptology and rapid searches of unstructured databases.
“Quantum computing could be potentially transformative, enabling us to solve problems that are impossible or impractical to solve today,” said Arvind Krishna, senior vice president and director of IBM Research, in a statement. “While quantum computers have traditionally been explored for cryptography, one area we find very compelling is the potential for practical quantum systems to solve problems in physics and quantum chemistry that are unsolvable today. This could have enormous potential in materials or drug design, opening up a new realm of applications.”
IARPA Award to IBM
The award is funded under the Logical Qubits (LogiQ) program of IARPA led by Dr. David Moehring. The LogiQ Program seeks to overcome the limitations of current quantum systems by building a logical qubit from a number of imperfect physical qubits.
Under the LogiQ program, IBM’s research team will continue to pursue the leading approach for building a universal quantum computer by using superconducting qubits. By encoding the superconducting qubits into a logical qubit, one should then be able to perform true quantum computation. These logical qubit designs will be foundational to future, more complex quantum computing systems.
IBM gives public access to its Quantum computers
IBM first opened public access to its quantum processors one year ago, to serve as an enablement tool for scientific research, a resource for university classrooms, and a catalyst of enthusiasm for the field. The quantum processor offered was composed of five superconducting qubits and housed at the IBM T.J. Watson Research Center in New York.
To date users have run more than 300,000 quantum experiments on the IBM Cloud. Researchers at Google have developed a similar device, although have not made it accessible to the public. Both of these computers use superconducting qubits built using techniques from the conventional computer chip industry.
IBM’s earlier universal quantum computing processors
Earlier IBM-developed processors include:
A 16 qubit processor that will allow for more complex experimentation than the previously available 5 qubit processor. It is freely accessible for developers, programmers and researchers to run quantum algorithms and experiments, work with individual quantum bits, and explore tutorials and simulations. Beta access is available through a new Software Development Kit available on GitHub https://github.com/IBM/qiskit-sdk-py.
IBM’s first prototype commercial processor with 17 qubits and leverages significant materials, device, and architecture improvements to make it the most powerful quantum processor created to date by IBM. It has been engineered to be at least twice as powerful as what is available today to the public on the IBM Cloud and it will be the basis for the first IBM Q early-access commercial systems.
“The significant engineering improvements announced today will allow IBM to scale future processors to include 50 or more qubits, and demonstrate computational capabilities beyond today’s classical computing systems,” said Arvind Krishna, senior vice president and director of IBM Research and Hybrid Cloud. “These powerful upgrades to our quantum systems, delivered via the IBM Cloud, allow us to imagine new applications and new frontiers for discovery that are virtually unattainable using classical computers alone.”
IBM has adopted a new metric to characterize the computational power of quantum systems: Quantum Volume. Quantum Volume accounts for the number and quality of qubits, circuit connectivity, and error rates of operations. IBM’s prototype commercial processor offers a significant improvement in the Quantum Volume. Over the next few years, IBM plans to continue to push the technology aggressively and aims to significantly increase the Quantum Volume of future systems by improving all aspects of the processors, including incorporating 50 or more qubits
In contrast to early quantum computers that cold run only single quantum algorithm, IBM’s computer is programmable just like a regular PC though it can only handle relatively small problems.
IBM advances closer to first true quantum computer
In 2015, IBM scientists unveiled two critical advances towards the realization of a practical quantum computer. For the first time, they showed the ability to detect and measure both kinds of quantum errors simultaneously, as well as demonstrated a new, square quantum bit circuit design that is the only physical architecture that could successfully scale to larger dimensions.
“What we’ve done thus far is to demonstrate some of the concepts of error correction and detection,” says Jerry Chow at IBM’s Thomas J. Watson Research Center in Yorktown Heights, New York. “What we’re doing with this programme is aiming for larger system sizes which permit the ability to encode a logical qubit.”
Chow says they need around 20 physical qubits to create one logical qubit, but packing the qubits close together will be tricky. “When you put many of them together, you don’t know that they are going to work the same way as when you just have one,” he says. “How you properly engineer this larger chip is going to be a big challenge.
LogiQ envisions that program success will require a multi-disciplinary approach to come up with new technical solutions that will better deal with the fragility of quantum information due to system imperfections, errors and environmental influences.
Detecting quantum errors
The ability to detect and deal with errors when manipulating quantum systems is a fundamental requirement for fault-tolerant quantum computing.
Unlike classical computer, which is based on binary bit and can have only two values, quantum computer is based on quantum bit (Qubit) that can hold a value of 1 or 0 as well as both values at the same time, described as superposition and simply denoted as “0+1”. This superposition property is what allows quantum computers to test every possible solution simultaneously and choose the correct solution amongst millions of possibilities in a time much faster than a conventional computer. The sign of this superposition is important because both states 0 and 1 have a phase relationship to each other.
One of the great challenges for scientists seeking to harness the power of quantum computing is controlling or removing quantum decoherence – the creation of errors in calculations caused by interference from factors such as heat, electromagnetic radiation, and material defects. The errors are especially acute in quantum machines, since quantum information is so fragile.
Two types of errors can occur on such a superposition state. One is called a bit-flip error, which simply flips a 0 to a 1 and vice versa. Quantum bit (Qubit) is also vulnerable to phase-flip errors, which flips the sign of the phase relationship between 0 and 1 in a superposition state.
Quantum Error correction critical in Building Practical Quantum computers
Unlike classical bits that are subject to only digital bit-flip errors, quantum bits are susceptible to a much larger spectrum of errors, for which any complete quantum error-correcting code must account. Quantum error correction is a critical requirement for building a practical and reliable large-scale quantum computer.
Determining the joint quantum information in the code qubits is an essential step for quantum error correction because directly measuring the code qubits destroys the information contained within them.
Quantum information is very fragile because all existing qubit technologies lose their information when interacting with matter and electromagnetic radiation. Theorists have found ways to preserve the information much longer by spreading information across many physical qubits.
Classical error correction employs redundancy for instance by storing the information multiple times, and—if these copies are later found to disagree—just take a majority vote; Copying quantum information is not possible due to the no-cloning theorem. But it is possible to spread the information of one qubit onto a highly entangled state of several (physical) qubits, even hundreds or thousands of them.
One of the error correction schemes is “Surface code” which spreads quantum information across many qubits. It allows for only nearest neighbor interactions to encode one logical qubit, making it sufficiently stable to perform error-free operations.
“Up until now, researchers have been able to detect bit-flip or phase-flip quantum errors, but never the two together. Previous work in this area, using linear arrangements, only looked at bit-flip errors offering incomplete information on the quantum state of a system and making them inadequate for a quantum computer,” said Jay Gambetta, a manager in the IBM Quantum Computing Group.
“Our four qubit results take us past this hurdle by detecting both types of quantum errors and can be scalable to larger systems, as the qubits are arranged in a square lattice as opposed to a linear array.”
IBM’s novel, quantum bit circuit design, based on a square lattice of four supercooled, superconducting qubits on a chip roughly one-quarter-inch square shows the best potential to scale to much larger dimensions.
Because these qubits can be designed and manufactured using standard silicon fabrication techniques, IBM anticipates that once a handful of superconducting qubits can be manufactured reliably and repeatedly, and controlled with low error rates, there will be no fundamental obstacle to demonstrating error correction in larger lattices of qubits.
The work at IBM was funded in part by the IARPA (Intelligence Advanced Research Projects Activity) multi-qubit-coherent-operations program.
IBM’s 3D qubit
In 2014, Scientists at the IBM research used 3D qubit to extend the quantum state up to 100 microseconds. This amount of time is sufficient to employ error correction algorithms to correct for errors in computation.
The 3D superconducting qubit is about 1 millimeter in length and suspended in the center of a cavity on a sapphire chip. Performance is measured by passing microwave signals to the device’s connectors. IBM officials said that the design team is confident that it can scale up the system to hundreds of thousands of qubits.
Of many viable approaches to quantum computation, IBM has chosen superconducting qubits that can utilize the microfabrication techniques of silicon and amenable for scaling up.
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