Instruct: Given a question, retrieve passages that can help answer the question.
Query: What is a recent development in quantum computation?
IBM unveils its first commercial quantum computer, the IBM Q System One [210]
While a classical 3-bit state and a quantum 3-qubit state are each eight-dimensional vectors, they are manipulated quite differently for classical or quantum computation. For computing in either case, the system must be initialized, for example into the all-zeros string, formula_28, corresponding to the vector (1,0,0,0,0,0,0,0). In classical randomized computation, the system evolves according to the application of stochastic matrices, which preserve that the probabilities add up to one (i.e., preserve the L1 norm). In quantum computation, on the other hand, allowed operations are unitary matrices, which are effectively rotations (they preserve that the sum of the squares add up to one, the Euclidean or L2 norm). (Exactly what unitaries can be applied depend on the physics of the quantum device.) Consequently, since rotations can be undone by rotating backward, quantum computations are reversible. (Technically, quantum operations can be probabilistic combinations of unitaries, so quantum computation really does generalize classical computation. See quantum circuit for a more precise formulation.)
Topological quantum computers are equivalent in computational power to other standard models of quantum computation, in particular to the quantum circuit model and to the quantum Turing machine model. That is, any of these models can efficiently simulate any of the others. Nonetheless, certain algorithms may be a more natural fit to the topological quantum computer model. For example, algorithms for evaluating the Jones polynomial were first developed in the topological model, and only later converted and extended in the standard quantum circuit model.
The company hosts a cloud computing platform called Forest, which gives developers access to quantum processors so they can write quantum algorithms for testing purposes. The computing platform is based on a custom instruction language the company developed called Quil, which stands for Quantum Instruction Language. Quil facilitates hybrid quantum/classical computing, and programs can be built and executed using open source Python tools. As of June 2017, the platform allows coders to write quantum algorithms for a simulation of a quantum chip with 36 qubits.
Hans Briegel has developed fundamental concepts in the field of quantum information, quantum computing and quantum communication. In 2001, together with Robert Raussendorf, he introduced the concept of a one-way quantum computer or measurement-based quantum computer model, which presented a new paradigm for building a quantum computer. According to Thomson Reuter’s analysis, the publication of this work is the second most-often cited publication in the field of quantum computing research in the first decade of the 21st century. Together with his work in cluster and graph states, it led to a completely new understanding of entanglement as a resource for quantum information processing. The concept of the quantum repeater, presented by Hans Briegel and his colleagues in 1998, plays an important role in quantum communication.
Liquid state NMR Quantum Information Processing was first theoretically introduced independently by Cory, Fahmy and Havel and Gershenfeld and Chuang in 1997. Some early success was obtained in performing quantum algorithms in NMR systems due to the relative maturity of NMR technology. For instance, in 2001 researchers at IBM reported the successful implementation of Shor's algorithm in a 7-qubit NMR quantum computer. However, even from the early days, it was recognized that NMR quantum computers would never be very useful due to the poor scaling of the signal to noise ratio in such systems. More recent work, particularly by Caves and others, shows that all experiments in liquid state bulk ensemble NMR quantum computing to date do not possess quantum entanglement, thought to be required for quantum computation. Hence NMR quantum computing experiments are likely to have been only classical simulations of a quantum computer.
Quantum complexity theory has been developed for studying computational complexity of quantum computing. It is used in post-quantum cryptography, which consists of designing cryptographic protocols that will resist to attacks with quantum computers, when such computers will really exist.
Carbon 12 purified for longer coherence times[103] Lifetime of qubits extended to hundreds of milliseconds[104] Quantum control of photons[105] Quantum entanglement demonstrated over 240 micrometres[106] Qubit lifetime extended by factor of 1000[107] First electronic quantum processor created[108] Six-photon graph state entanglement used to simulate the fractional statistics of anyons living in artificial spin-lattice models[109] Single molecule optical transistor[110] NIST reads, writes individual qubits[111] NIST demonstrates multiple computing operations on qubits[112] First large-scale topological cluster state quantum architecture developed for atom-optics[113] A combination of all of the fundamental elements required to perform scalable quantum computing through the use of qubits stored in the internal states of trapped atomic ions shown[114] Researchers at University of Bristol demonstrate Shor's algorithm on a silicon photonic chip[115] Quantum Computing with an Electron Spin Ensemble[116] Scalable flux qubit demonstrated[117] Photon machine gun developed for quantum computing[118] Quantum algorithm developed for differential equation systems[119] First universal programmable quantum computer unveiled[120] Scientists electrically control quantum states of electrons[121] Google collaborates with D-Wave Systems on image search technology using quantum computing[122] A method for synchronizing the properties of multiple coupled CJJ rf-SQUID flux qubits with a small spread of device parameters due to fabrication variations was demonstrated[123]
QxBranch provides predictive analytics services to firms in the banking and finance industries. The company also develops software products for quantum computing technologies, including developer tools and interfaces for quantum computers, as well as quantum computing simulators. Additionally, the company provides consulting and research and development for businesses that may be improved through quantum computing methods, including in the development of adiabatic quantum computing methods for machine learning applications.
He then also applied quantum entanglement to optical quantum computation, where in 2005, he performed the first implementation of one-way quantum computation. This is a protocol based on quantum measurement as proposed by Knill, Laflamme and Milburn. Most recently, it has been shown that one-way quantum computation can be used to implement blind quantum computing. This solves a problem in Cloud computing, namely that, whatever algorithm a client employs on a quantum server is completely unknown, i.e. blind, to the operator of the server.
During the 2010s, his work has continued on exploring quantum dots as a platform for building both quantum repeaters and quantum computers. One highlight was the co-first demonstration (with Ataç İmamoğlu's group) of entanglement between a spin in a quantum dot and a photon emitted by it. Work on exciton-polaritons continued, and since 2012, Yamamoto has pioneered the development of an optical computer, inspired by developments in quantum annealing and adiabatic quantum computing.
A recent review by Mikhail Dyakonov in IEEE Spectrum argues that practical quantum computers are not likely to be implemented. He says: "There is a tremendous gap between the rudimentary but very hard experiments that have been carried out with a few qubits and the extremely developed quantum-computing theory, which relies on manipulating thousands to millions of qubits to calculate anything useful. That gap is not likely to be closed anytime soon."
Childs is known for his work on quantum computing, especially on the development of quantum algorithms.
He helped to develop the concept of a quantum walk
leading to an example of exponential quantum speedup
and algorithms for spatial search, formula evaluation, and universal computation
He also developed quantum algorithms for algebraic problems and for simulating quantum systems.
Examples of such applications include quantum key distribution, clock synchronization, protocols for distributed system problems such as leader election or byzantine agreement, extending the baseline of telescopes, as well as position verification, secure identification and two-party cryptography in the noisy-storage model. A quantum internet also enables secure access to a quantum computer in the cloud. Specifically, a quantum internet enables very simple quantum devices to connect to a remote quantum computer in such a way that computations can be performed there without the quantum computer finding out what this computation actually is.
Although quantum computers may be faster than classical computers for some problem types, those described above cannot solve any problem that classical computers cannot already solve. A Turing machine can simulate these quantum computers, so such a quantum computer could never solve an undecidable problem like the halting problem. The existence of "standard" quantum computers does not disprove the Church–Turing thesis. It has been speculated that theories of quantum gravity, such as M-theory or loop quantum gravity, may allow even faster computers to be built. Currently, "defining" computation in such theories is an open problem due to the "problem of time", i.e., there currently exists no obvious way to describe what it means for an observer to submit input to a computer and later receive output.
As the field has progressed new quantum algorithms have been developed which provide short and long term routes towards the demonstration of the superiority of quantum computers over their classical counterparts. Cluster state computation is now generally accepted as the approach that will be used to develop a fully fledged quantum computer. Whilst development of quantum computer will require the synthesis of many different aspects of integrated optics, boson sampling seeks to demonstrate the power of quantum computation via technologies readily available and is therefore a very promising near term algorithm to doing so. In fact shortly after its proposal there were several small scale experimental demonstrations of the boson sampling algorithm
Ion trapped in optical trap[124] Optical quantum computer with three qubits calculated the energy spectrum of molecular hydrogen to high precision[125] First germanium laser brings us closer to 'optical computers'[126] Single electron qubit developed[127] Quantum state in macroscopic object[128] New quantum computer cooling method developed[129] Racetrack ion trap developed[130] Evidence for a Moore-Read state in the ν = 5 / 2 {\displaystyle \nu =5/2} quantum Hall plateau,[131] which would be suitable for topological quantum computation Quantum interface between a single photon and a single atom demonstrated[132] LED quantum entanglement demonstrated[133] Multiplexed design speeds up transmission of quantum information through a quantum communications channel[134] Two photon optical chip[135] Microfabricated planar ion traps[136][137] Qubits manipulated electrically, not magnetically[138]
Devitt's research has focused on the design of practical large-scale systems architectures for quantum computing and communications system. He published the first architecture, in an atom-optical system, that utilised techniques in topological quantum error correction that could be conceptually scaled to an arbitrary number of encoded qubits. In 2014, in collaboration with NTT Communications and TU Wien, he developed a design for a scalable system using the Nitrogen-vacancy center and in 2017 he developed a large-scale system design for Ion trap quantum computing in collaboration with the University of Sussex. Devitt has also worked in the development of scalable Quantum networks, developing designs for what is now known as 2nd and 3rd generation quantum repeaters and inventing, with scientists in Japan and Australia, a quantum version of Sneakernets.
As a theoretician, Peter Zoller has written major works on the interaction of laser light and atoms. In addition to fundamental developments in quantum optics he has succeeded in bridging quantum information and solid state physics. The model of a quantum computer, suggested by him and Ignacio Cirac in 1995, is based on the interaction of lasers with cold ions confined in an electromagnetic trap. The principles of this idea have been implemented in experiments over recent years and it is considered one of the most promising concepts for the development of a scalable quantum computer. Zoller and his researcher colleagues have also managed to link quantum physics with solid state physics. One of his suggestions has been to build a quantum simulator with cold atoms and use it to research hitherto unexplained phenomena in high temperature superconductors. Zoller's ideas and concepts attract widespread interest within the scientific community and his works are highly cited.
In March 2017, IBM announced an industry-first initiative to build commercially available universal quantum computing systems called IBM Q. The company also released a new API (Application Program Interface) for the IBM Quantum Experience that enables developers and programmers to begin building interfaces between its existing five quantum bit (qubit) cloud-based quantum computer and classical computers, without needing a deep background in quantum physics.
Post-quantum cryptography (sometimes referred to as quantum-proof, quantum-safe or quantum-resistant) refers to cryptographic algorithms (usually public-key algorithms) that are thought to be secure against an attack by a quantum computer. , this is not true for the most popular public-key algorithms, which can be efficiently broken by a sufficiently strong hypothetical quantum computer. The problem with currently popular algorithms is that their security relies on one of three hard mathematical problems: the integer factorization problem, the discrete logarithm problem or the elliptic-curve discrete logarithm problem. All of these problems can be easily solved on a sufficiently powerful quantum computer running Shor's algorithm. Even though current, publicly known, experimental quantum computers lack processing power to break any real cryptographic algorithm, many cryptographers are designing new algorithms to prepare for a time when quantum computing becomes a threat. This work has gained greater attention from academics and industry through the PQCrypto conference series since 2006 and more recently by several workshops on Quantum Safe Cryptography hosted by the European Telecommunications Standards Institute (ETSI) and the Institute for Quantum Computing.
Laflamme's research focuses on understanding the impact of manipulating information using the laws of quantum mechanics, the development of methods to protect quantum information against noise through quantum control and quantum error correction for quantum computing and cryptography, the implementation of ideas and concepts of quantum information processing using nuclear magnetic resonance to develop scalable methods of control of quantum systems, and the development of blueprints for quantum information processors such as linear optical quantum computing.
Continuous-variable quantum information is the area of quantum information science that makes use of physical observables, like the strength of an electromagnetic field, whose numerical values belong to continuous intervals. One primary application is quantum computing. In a sense, continuous-variable quantum computation is "analog", while quantum computation using qubits is "digital." In more technical terms, the former makes use of Hilbert spaces that are infinite-dimensional, while the Hilbert spaces for systems comprising collections of qubits are finite-dimensional. One motivation for studying continuous-variable quantum computation is to understand what resources are necessary to make quantum computers more powerful than classical ones.
Researchers from the University of Illinois at Urbana–Champaign use the Zeno Effect, repeatedly measuring the properties of a photon to gradually change it without actually allowing the photon to reach the program, to search a database without actually "running" the quantum computer.[26] Vlatko Vedral of the University of Leeds and colleagues at the universities of Porto and Vienna found that the photons in ordinary laser light can be quantum mechanically entangled with the vibrations of a macroscopic mirror.[27] Samuel L. Braunstein at the University of York along with the University of Tokyo and the Japan Science and Technology Agency gave the first experimental demonstration of quantum telecloning.[28] Professors at the University of Sheffield develop a means to efficiently produce and manipulate individual photons at high efficiency at room temperature.[29] New error checking method theorized for Josephson junction computers.[30] First 12 qubit quantum computer benchmarked by researchers at the Institute for Quantum Computing and the Perimeter Institute for Theoretical Physics in Waterloo, as well as MIT, Cambridge.[31] Two dimensional ion trap developed for quantum computing.[32] Seven atoms placed in stable line, a step on the way to constructing a quantum gate, at the University of Bonn.[33] A team at Delft University of Technology in the Netherlands created a device that can manipulate the "up" or "down" spin-states of electrons on quantum dots.[34] University of Arkansas develops quantum dot molecules.[35] Spinning new theory on particle spin brings science closer to quantum computing.[36] University of Copenhagen develops quantum teleportation between photons and atoms.[37] University of Camerino scientists develop theory of macroscopic object entanglement, which has implications for the development of quantum repeaters.[38] Tai-Chang Chiang, at Illinois at Urbana–Champaign, finds that quantum coherence can be maintained in mixed-material systems.[39] Cristophe Boehme, University of Utah, demonstrates the feasibility of reading spin-data on a silicon-phosphorus quantum computer.[40]
Graphene quantum dot qubits[76] Quantum bit stored[77] 3D qubit-qutrit entanglement demonstrated[78] Analog quantum computing devised[79] Control of quantum tunneling[80] Entangled memory developed[81] Superior NOT gate developed[82] Qutrits developed[83] Quantum logic gate in optical fiber[84] Superior quantum Hall Effect discovered[85] Enduring spin states in quantum dots[86] Molecular magnets proposed for quantum RAM[87] Quasiparticles offer hope of stable quantum computer[88] Image storage may have better storage of qubits[89] Quantum entangled images[90] Quantum state intentionally altered in molecule[91] Electron position controlled in silicon circuit[92] Superconducting electronic circuit pumps microwave photons[93] Amplitude spectroscopy developed[94] Superior quantum computer test developed[95] Optical frequency comb devised[96] Quantum Darwinism supported[97] Hybrid qubit memory developed[98] Qubit stored for over 1 second in atomic nucleus[99] Faster electron spin qubit switching and reading developed[100] Possible non-entanglement quantum computing[101] D-Wave Systems claims to have produced a 128 qubit computer chip, though this claim has yet to be verified.[102]