The 2000s (2000-July 2021)
This post covers all the recent quantum computing advancements surrounding the last 20 years. When possible, I have included the documents, names, locations, updates. A lot has happened since 2000. Although most of this data in this post comes from public data at the respective organizations, universities, science centers, government press releases, Wikipedia, I have painstakingly included many documents, links, pictures, and some downloadable files related to the announcements. Each year marks a significant event unrelated to the quantum world but sets the course for the year ahead. My primary motivation is to learn about quantum computing as I blog. I read my stuff, and that's how I learn.
The year 2000
The spacecraft 'NEAR Shoemaker' enters orbit around asteroid 433 Eros, the first spacecraft to orbit an asteroid. (NASA)
Meanwhile:
Arun K. Pati and Samuel L. Braunstein proved the quantum no-deleting theorem. This is dual to the no-cloning theorem which shows that one cannot delete a copy of an unknown qubit. Together with the stronger no-cloning theorem, the no-deleting theorem has important implication, i.e., quantum information can neither be created nor be destroyed.
An interesting fact about Arun Pati is that Arun has made pioneering contributions in the area of quantum information, a subject that needs its own post.
Next we go to Germany (Technical University of Munich)
First working 5-qubit NMR computer demonstrated at the Technical University of Munich.
Here is the document:
Chemical Enigneering of an NMR Quantum Computer
R. Marx, A. F. Fahmy, J. M. Myers, W. Bermel, S. J. Glaser,
in: Quantum Computing, Eds.: E. Donkor and A. R. Pirich, Proceedings of SPIE Vol. 4047, pp. 131-138 (2000).
There are publications dating back to 1986 -2021, a wealth of information in quantum computing research.
https://www.tum.de/en/about-tum/news/quantum-technology
Next we are going to the USA.
First execution of order finding (part of Shor's algorithm) at IBM's Almaden Research Center and Stanford University.
I have not found the document yet!
Meanwhile in Los Alamos National Lab, First working 7-qubit NMR computer demonstrated.
In March, scientists at Los Alamos National Laboratory announced the development of a 7-qubit quantum computer within a single drop of liquid. The quantum computer uses nuclear magnetic resonance (NMR) to manipulate particles in the atomic nuclei of molecules of trans-crotonic acid, a simple fluid consisting of molecules made up of six hydrogen and four carbon atoms
- Researchers at IBM-Almaden Research Center developed what they claimed was the most advanced quantum computer to date in August. The 5-qubit quantum computer was designed to allow the nuclei of five fluorine atoms to interact with each other as qubits, be programmed by radio frequency pulses and be detected by NMR instruments similar to those used in hospitals
Michael A Nielsen and Isaac Chuang published what is called the bible of quantum computing. I will cover an entire post to this book.
Dr. Michael Nielsen was born in Brisbane, Australia in 1974, and was educated at the University of Queensland, obtaining postgraduate degrees in mathematics and physics, before being awarded his PhD in physics at the University of New Mexico in 1998. He is currently the Tolman Postdoctoral Fellow and a Fulbright Scholar at the California Institute of Technology.
The standard textbook, Quantum Computation and Quantum Information, by Michael Nielsen and Isaac Chuang is published.
2001
Human genome known as First draft of the complete human genome is published in 'Nature (journal) or Nature
The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.
Meanwhile:
First execution of Shor's algorithm at IBM's Almaden Research Center and Stanford University. The number 15 was factored using 1018 identical molecules, each containing seven active nuclear spins.
Noah Linden and Sandu Popescu proved that the presence of entanglement is a necessary condition for a large class of quantum protocols. This, coupled with Braunstein's result (1999), called the validity of NMR quantum computation into question. (I will cover this in a different post.)
Emanuel Knill, Raymond Laflamme, and Gerard Milburn show that optical quantum computing is possible with single photon sources, linear optical elements, and single photon detectors, launching the field of linear optical quantum computing.
Robert Raussendorf and Hans Jürgen Briegel propose measurement-based quantum computation.
2002
The Quantum Information Science and Technology Road mapping Project, involving some of the main participants in the field, laid out the Quantum computation roadmap.
The Institute for Quantum Computing was established at the University of Waterloo in Waterloo, Ontario by Mike Lazaridis, Raymond Laflamme and Michele Mosca.
2003
Implementation of the Deutsch–Jozsa algorithm (see pictures, david to the right) on an ion-trap quantum computer at the University of Innsbruck.
Note: The Deutsch–Jozsa algorithm is a deterministicquantum algorithm proposed by David Deutsch and Richard Jozsa in 1992 with improvements by Richard Cleve, Artur Ekert, Chiara Macchiavello, and Michele Mosca in 1998. Although of little current practical use, it is one of the first examples of a quantum algorithm that is exponentially faster than any possible deterministic classical algorithm.
* Deutsch–Jozsa algorithm: The goal is to decide whether is constant or balanced by making as few function evaluations as possible. Classically, it requires function evaluations in the worst case. Using the Deutsch-Jozsa algorithm, the question can be answered with just one function evaluation.
Todd D. Pittman and collaborators at Johns Hopkins University, Applied Physics Laboratory and independently Jeremy L. O'Brien and collaborators at the University of Queensland, demonstrate quantum controlled-not gates using only linear optical elements.
First implementation of a CNOT quantum gate according to the Cirac–Zoller proposal by a group at the University of Innsbruck led by Rainer Blatt
DARPA Quantum Network becomes fully operational on October 23, 2003.
The Institute for Quantum Optics and Quantum Information (IQOQI) was established in Innsbruck and Vienna, Austria, by the founding directors Rainer Blatt, Hans Jürgen Briegel, Rudolf Grimm, Anton Zeilinger and Peter Zoller.
2004
First working pure state NMR quantum computer (based on parahydrogen) demonstrated at Oxford University and University of York.
Physicists at the University of Innsbruck show deterministic quantum-state teleportation between a pair of trapped calcium ions.
First five-photon entanglement demonstrated by Jian-Wei Pan's group at the University of Science and Technology of China, the minimal number of qubits required for universal quantum error correction.
2005
University of Illinois at Urbana–Champaign scientists demonstrate quantum entanglement of multiple characteristics, potentially allowing multiple qubits per particle.
Two teams of physicists measured the capacitance of a Josephson junction for the first time. The methods could be used to measure the state of quantum bits in a quantum computer without disturbing the state.
In December, the first quantum byte, or qubyte, is announced to have been created by scientists at the Institute for Quantum Optics and Quantum Information and the University of Innsbruck in Austria.
Harvard University and Georgia Institute of Technology researchers succeeded in transferring quantum information between "quantum memories" – from atoms to photons and back again.
2006
Materials Science Department of Oxford University, cage a qubit in a "bucky ball" (a molecule of buckminsterfullerene), and demonstrated quantum "bang-bang" error correction.[43]
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.
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.
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.
Professors at the University of Sheffield develop a means to efficiently produce and manipulate individual photons at high efficiency at room temperature.
New error checking method theorized for Josephson junction computers.
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.
Two dimensional ion trap developed for quantum computing.
Seven atoms placed in stable line, a step on the way to constructing a quantum gate, at the University of Bonn.
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.
University of Arkansas develops quantum dot molecules.
Spinning new theory on particle spin brings science closer to quantum computing.
University of Copenhagen develops quantum teleportation between photons and atoms.
University of Camerino scientists develop theory of macroscopic object entanglement, which has implications for the development of quantum repeaters.
Tai-Chang Chiang, at Illinois at Urbana–Champaign, finds that quantum coherence can be maintained in mixed-material systems.
Cristophe Boehme, University of Utah, demonstrates the feasibility of reading spin-data on a silicon-phosphorus quantum computer.
2007
Subwavelength waveguide developed for light.
Single photon emitter for optical fibers developed.
Six-photon one-way quantum computer is created in lab.
New material proposed for quantum computing.
Single atom single photon server devised.
First use of Deutsch's Algorithm in a cluster state quantum computer.
University of Cambridge develops electron quantum pump.
Superior method of qubit coupling developed.
Successful demonstration of controllably coupled qubits.
Breakthrough in applying spin-based electronics to silicon.
Scientists demonstrate quantum state exchange between light and matter.
Diamond quantum register developed.
Controlled-NOT quantum gates on a pair of superconducting quantum bits realized.
Scientists contain, study hundreds of individual atoms in 3D array.
Nitrogen in buck yball molecule used in quantum computing
Large number of electrons quantum coupled.
Spin-orbit interaction of electrons measured.
Atoms quantum manipulated in laser light.
Light pulses used to control electron spins.
Quantum effects demonstrated across tens of nanometers.
Light pulses used to accelerate quantum computing development.
Quantum RAM blueprint unveiled.
Model of quantum transistor developed
Long distance entanglement demonstrated.
Photonic quantum computing used to factor number by two independent labs.
Quantum bus developed by two independent labs.
Superconducting quantum cable developed.
Transmission of qubits demonstrated.
Superior qubit material devised.
Single electron qubit memory.
Bose-Einstein condensate quantum memory developed.
D-Wave Systems demonstrates use of a 28-qubit quantum annealing computer.
New cryonic method reduces decoherence and increases interaction distance, and thus quantum computing speed.
Photonic quantum computer demonstrated.
Graphene quantum dot spin qubits proposed.
2008
Graphene quantum dot qubits
Quantum bit stored[
3D qubit-qutrit entanglement demonstrated
Analog quantum computing devised
Control of quantum tunneling
Entangled memory developed
Superior NOT gate developed
Qutrits developed
Quantum logic gate in optical fiber
Superior quantum Hall Effect discovery:
The quantum Hall effect (QHE) and its relation to fundamental physical constants was discovered in 1980 by Klaus von Klitzing for which he received a Nobel prize in 1985. Read an interview with Klaus here.
Enduring spin states in quantum dots
Molecular magnets proposed for quantum RAM
Quasiparticles offer hope of stable quantum computer
Image storage may have better storage of qubits
Quantum entangled images
Quantum state intentionally altered in molecule
Electron position controlled in silicon circuit
Superconducting electronic circuit pumps microwave photons
Amplitude spectroscopy developed (The energy-level structure of a quantum system, which has a fundamental role in its behavior, can be observed as discrete lines and features in absorption and emission spectra.)
Download the PDF document free here
Superior quantum computer test developed
Optical frequency comb devised
Quantum Darwinism supported
Hybrid qubit memory developed
Qubit stored for over 1 second in atomic nucleus
Faster electron spin qubit switching and reading developed
Possible non-entanglement quantum computing
D-Wave Systems claims to have produced a 128 qubit computer chip, though this claim has yet to be verified.
2009
Carbon 12 purified for longer coherence times
Lifetime of qubits extended to hundreds of milliseconds
Quantum control of photons
Quantum entanglement demonstrated over 240 micrometres
Qubit lifetime extended by factor of 1000
First electronic quantum processor created
Six-photon graph state entanglement used to simulate the fractional statistics of anyons living in artificial spin-lattice models
Single molecule optical transistor
NIST reads, writes individual qubits
NIST demonstrates multiple computing operations on qubits
First large-scale topological cluster state quantum architecture developed for atom-optics
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
Researchers at University of Bristol demonstrate Shor's algorithm on a silicon photonic chip
Quantum Computing with an Electron Spin Ensemble
Scalable flux qubit demonstrated
Photon machine gun developed for quantum computing
Quantum algorithm developed for differential equation systems
First universal programmable quantum computer unveiled
Scientists electrically control quantum states of electrons[
Google collaborates with D-Wave Systems on image search technology using quantum computing
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
Realization of Universal Ion Trap Quantum Computation with Decoherence Free Qubits
First chip-scale quantum computer
2010s
2010
On January 12, 2010, a 7.0 magnitude earthquake devastates Haiti, killing more than 230,000 and destroying the nation's infrastructure. On January 27, 2010, Apple Computer unveils the iPad tablet computer
Meanwhile:
Ion trapped in optical trap
Optical quantum computer with three qubits calculated the energy spectrum of molecular hydrogen to high precision
First germanium laser brings us closer to optical computers
Single electron qubit developed
Quantum state in macroscopic object
New quantum computer cooling method developed
Racetrack ion trap developed
Evidence for a Moore-Read state plateau, which would be suitable for topological quantum computation
Quantum interface between a single photon and a single atom demonstrated
LED quantum entanglement demonstrated
Multiplexed design speeds up transmission of quantum information through a quantum communications channel
Two photon optical chip
Microfabricated planar ion traps
Boson sampling technique proposed by Aaronson and Arkhipov.
Quantum dot qubits manipulated electrically, not magnetically
2011
Novak Djokovic Wins Fourth Wimbledon Title in Straight Sets
Meanwhile:
Entanglement in a solid-state spin ensemble
NOON photons in superconducting quantum integrated circuit
Quantum antenna
Multimode quantum interference
Magnetic Resonance applied to quantum computing
Quantum pen
Atomic "Racing Dual"
14 qubit register
D-Wave claims to have developed quantum annealing and introduces their product called D-Wave One. The company claims this is the first commercially available quantum computer
Repetitive error correction demonstrated in a quantum processor
Diamond quantum computer memory demonstrated
Qmodes developed
Decoherence suppressed
Simplification of controlled operations Ions entangled using microwaves
Practical error rates achieved
Quantum computer employing Von Neumann architecture
Quantum spin Hall topological insulator
Two Diamonds Linked by Quantum Entanglement could help develop photonic processors
2012
London Olympics
Meanwhile:
D-Wave claims a quantum computation using 84 qubits.
Physicists create a working transistor from a single atom
A method for manipulating the charge of nitrogen vacancy-centres in diamond
Reported creation of a 300 qubit/particle quantum simulator.
Demonstration of topologically protected qubits with an eight-photon entanglement, a robust approach to practical quantum computing
1QB Information Technologies (1QBit) founded. World's first dedicated quantum computing software company.
First design of a quantum repeater system without a need for quantum memories[187]
Decoherence suppressed for 2 seconds at room temperature by manipulating Carbon-13 atoms with lasers.
Theory of Bell-based randomness expansion with reduced assumption of measurement independence.
New low overhead method for fault-tolerant quantum logic developed, called lattice surgery
2013
Hurricane Sandy devested parts of USA.
Meanwhile:
Coherence time of 39 minutes at room temperature (and 3 hours at cryogenic temperatures) demonstrated for an ensemble of impurity-spin qubits in isotopically purified silicon.
Extension of time for qubit maintained in superimposed state for ten times longer than what has ever been achieved before
First resource analysis of a large-scale quantum algorithm using explicit fault-tolerant, error-correction protocols was developed for factoring
2014
In November 2014, President Obama signed an executive order that would save “five million people from deportation and allow many to work legally, although it offers no path to citizenship.”
Meanwhile:
Documents leaked by Edward Snowden confirm the Penetrating Hard Targets project, by which the National Security Agency seeks to develop a quantum computing capability for cryptography purposes.
Researchers in Japan and Austria publish the first large-scale quantum computing architecture for a diamond based system
Scientists at the University of Innsbruck do quantum computations on a topologically encoded qubit which is encoded in entangled states distributed over seven trapped-ion qubits
Scientists transfer data by quantum teleportation over a distance of 10 feet (3.048 meters) with zero percent error rate, a vital step towards a quantum Internet.
2015
The discoveries made on Pluto
After travelling for nine years, NASA's Horizons spacecraft finished its first fly-by of Pluto, taking photos of Pluto and its largest moon. The photos revealed the presence of ice-mountains and two new moons, Kerberos and Styx.
Meanwhile:
Optically addressable nuclear spins in a solid with a six-hour coherence time.
Quantum information encoded by simple electrical pulses.
Quantum error detection code using a square lattice of four superconducting qubits.
D-Wave Systems Inc. announced on June 22 that it had broken the 1,000-qubit barrier.
A two-qubit silicon logic gate is successfully developed.
A quantum computer, along with quantum superposition and entanglement, is emulated by a classical analog computer, with the result that the fully classical system behaves like a true quantum computer.
2016
Michael Phelps ended his career with team gold in the 4x100m medley relay at Rio 2016.
Physicists led by Rainer Blatt joined forces with scientists at MIT, led by Isaac Chuang, to efficiently implement Shor's algorithm in an ion-trap based quantum computer.[209]
IBM releases the Quantum Experience, an online interface to their superconducting systems. The system is immediately used to publish new protocols in quantum information processing
Google, using an array of 9 superconducting qubits developed by the Martinis group and UCSB, simulates a hydrogen molecule.
Scientists in Japan and Australia invent the quantum version of a Sneakernet communications system
2017 - Women march in the USA
D-Wave Systems Inc. announces general commercial availability of the D-Wave 2000Q quantum annealer, which it claims has 2000 qubits.
Blueprint for a microwave trapped ion quantum computer published. IBM unveils 17-qubit quantum computer—and a better way of benchmarking it.
Scientists build a microchip that generates two entangled qubits each with 10 states, for 100 dimensions total.
Microsoft reveals Q Sharp, a quantum programming language integrated with Visual Studio. Programs can be executed locally on a 32-qubit simulator, or a 40-qubit simulator on Azure.
Kazi Saabique Ahmed, the former intelligent systems advisor of DARPA in collaboration with the researchers of QuAIL develop the world's first user-interactive operating system to be used in commercial quantum computers. And Intel confirms development of a 17-qubit superconducting test chip.
IBM reveals a working 50-qubit quantum computer that can maintain its quantum state for 90 microseconds.
2018 -World cup
MIT scientists report the discovery of a new triple-photon form of light
Oxford researchers successfully use a trapped-ion technique, where they place two charged atoms in a state of quantum entanglement to speed up logic gates by a factor of 20 to 60 times, as compared with the previous best gates, translated to 1.6 microseconds long, with 99.8% precision.
QuTech successfully tests a silicon-based 2-spin-qubit processor.
Google announces the creation of a 72-qubit quantum chip, called "Bristlecone",achieving a new record.
Intel begins testing a silicon-based spin-qubit processor manufactured in the company's D1D Fab in Oregon.
Intel confirms development of a 49-qubit superconducting test chip, called "Tangle Lake".
Japanese researchers demonstrate universal holonomic quantum gates.
Integrated photonic platform for quantum information with continuous variables.
On December 17, 2018, the company IonQ introduced the first commercial trapped-ion quantum computer, with a program length of over 60 two-qubit gates, 11 fully connected qubits, 55 addressable pairs, one-qubit gate error <0.03% and two-qubit gate error <1.0%
On December 21, 2018, the National Quantum Initiative Act was signed into law by President Donald Trump, establishing the goals and priorities for a 10-year plan to accelerate the development of quantum information science and technology applications in the United States.
2019
IBM Q System One (2019), the first circuit-based commercial quantum computer
IBM unveils its first commercial quantum computer, the IBM Q System One, designed by UK-based Map Project Office and Universal Design Studio and manufactured by Goppion.
Austrian physicists demonstrate self-verifying, hybrid, variational quantum simulation of lattice models in condensed matter and high-energy physics using a feedback loop between a classical computer and a quantum co-processor.
Quantum Darwinism observed in diamond at room temperature.
A paper by Google's quantum computer research team was briefly available in late September 2019, claiming the project has reached quantum supremacy.
IBM reveals its biggest quantum computer yet, consisting of 53 qubits. The system goes online in October 2019.
University of Science and Technology of China researchers demonstrate boson sampling with 14 detected photons.
2020
UNSW Sydney develops a way of producing 'hot qubits' – quantum devices that operate at 1.5 Kelvin.
Griffith University, UNSW and UTS, in partnership with seven universities in the United States, develop noise cancelling for quantum bits via machine learning, taking quantum noise in a quantum chip down to 0%.
UNSW performs electric nuclear resonance to control single atoms in electronic devices.
University of Tokyo and Australian scientists create and successfully test a solution to the quantum wiring problem, creating a 2D structure for qubits. Such structure can be built using existing integrated circuit technology and has a considerably lower cross-talk.
16 January – Quantum physicists report the first direct splitting of one photon into three using spontaneous parametric down-conversion and which may have applications in quantum technology.11 February – Quantum engineers report that they have created artificial atoms in silicon quantum dots for quantum computing and that artificial atoms with a higher number of electrons can be more stable qubits than previously thought possible. Enabling silicon-based quantum computers may make it possible to reuse the manufacturing technology of "classical" modern-day computer chips among other advantages.
14 February – Quantum physicists develop a novel single-photon source which may allow to bridge semiconductor-based quantum-computers that use photons by converting the state of an electron spin to the polarization of a photon. They show that they can generate a single photon in a controlled way without the need for randomly formed quantum dots or structural defects in diamonds.
25 February – Scientists visualize a quantum measurement: by taking snapshots of ion states at different times of measurement via coupling of a trapped ion qutrit to the photon environment they show that the changes of the degrees of superpositions and therefore of probabilities of states after measurement happens gradually under the measurement influence.
2 March – Scientists report to have achieved repeated quantum non demolition measurements of an electron's spin in a silicon quantum dot: measurements that don't change the electron's spin in the process.
11 March – Quantum engineers report to have managed to control the nucleus of a single atom using only electric fields. This was first suggested to be possible in 1961 and may be used for silicon quantum computers that use single-atom spins without needing oscillating magnetic fields which may be especially useful for nanodevices, for precise sensors of electric and magnetic fields as well as for fundamental inquiries into quantum nature.
19 March – A US Army laboratory announces that its scientists analyzed a Rydberg sensor's sensitivity to oscillating electric fields over an enormous range of frequencies—from 0 to 10^12 Hertz (the spectrum to 0.3mm wavelength). The Rydberg sensor may potentially be used detect communications signals as it could reliably detect signals over the entire spectrum and compare favorably with other established electric field sensor technologies, such as electro-optic crystals and dipole antenna-coupled passive electronics.
23 March – Researchers report that they have found a way to correct for signal loss in a prototype quantum node that can catch, store and entangle bits of quantum information. Their concepts could be used for key components of quantum repeaters in quantum networks and extend their longest possible range.
15 April – Researchers demonstrate a proof-of-concept silicon quantum processor unit cell which works at 1.5 Kelvin – many times warmer than common quantum processors that are being developed. It may enable integrating classical control electronics with the qubit array and reduce costs substantially. The cooling requirements necessary for quantum computing have been called one of the toughest roadblocks in the field.
16 April – Scientists prove the existence of the Rashba effect in bulk perovskites. Previously researchers have hypothesized that the materials' extraordinary electronic, magnetic and optical properties – which make it a commonly used material for solar cells and quantum electronics – are related to this effect which to date hasn't been proven to be present in the material.
8 May – Researchers report to have developed a proof-of-concept of a quantum radar using quantum entanglement and microwaves which may potentially be useful for the development of improved radar systems, security scanners and medical imaging systems.
12 May – Researchers report to have developed a method to selectively manipulate a layered manganite's correlated electrons' spin state while leaving its orbital state intact using femtosecond X-ray laser pulses. This may indicate that orbitronics – using variations in the orientations of orbitals – may be used as the basic unit of information in novel IT devices.
19 May – Researchers report to have developed the first integrated silicon on-chip low-noise single-photon source compatible with large-scale quantum photonics.
11 June – Scientists report the generation of rubidium Bose–Einstein condensates (BECs) in the Cold Atom Laboratory aboard the International Space Station under microgravity which could enable improved research of BECs and quantum mechanics, whose physics are scaled to macroscopic scales in BECs, support long-term investigations of few-body physics, support the development of techniques for atom-wave interferometry and atom lasers and has verified the successful operation of the laboratory.
15 June – Scientists report the development of the smallest synthetic molecular motor, consisting of 12 atoms and a rotor of 4 atoms, shown to be capable of being powered by an electric current using an electron scanning microscope and moving even with very low amounts of energy due to quantum tunneling.
17 June – Quantum scientists report the development of a system that entangles two photon quantum communication nodes through a microwave cable that can send information in between without the photons ever being sent through, or occupying, the cable. On 12 June it was reported that they also, for the first time, entangled two phonons as well as erase information from their measurement after the measurement has been completed using delayed-choice quantum erasure.
13 August – Universal coherence protection is reported to have been achieved in a solid-state spin qubit, a modification that allows quantum systems to stay operational (or "coherent") for 10,000 times longer than before.
26 August – Scientists report that that ionizing radiation from environmental radioactive materials and cosmic rays may substantially limit the coherence times of qubits if they aren't shielded adequately.
28 August – Quantum engineers working for Google report the largest chemical simulation on a quantum computer – a Hartree-Fock approximation with Sycamore paired with a classical computer that analyzed results to provide new parameters for the 12-qubit system.
2 September – Researchers present an eight-user city-scale quantum communication network, located in Bristol, using already deployed fibres without active switching or trusted nodes.
21 September – Researchers report the achievement of quantum entanglement between the motion of a millimetre-sized mechanical oscillator and a disparate distant spin system of a cloud of atoms.
3 December – Chinese researchers claim to have achieved quantum supremacy, using a photonic peak 76-qubit system (43 average) known as Jiuzhang, which performed calculations at 100 trillion times the speed of classical supercomputers.
21 December – Publication of research of "counterfactual quantum communication" – whose first achievement was reported in 2017 – by which information can be exchanged without any physical particle traveling between observers and without quantum teleportation. The research suggests that this is based on some form of relation between the properties of modular angular momentum.
2021
6 January – Chinese researchers report that they have built the world's largest integrated quantum communication network, combining over 700 optical fibers with two QKD-ground-to-satellite links for a total distance between nodes of the network of networks of up to ~4,600 km.
13 January – Austrian researchers report the first realization of an entangling gate between two logical qubits encoded in topological quantum error-correction codes using a trapped-ion quantum computer with 10 ions.
15 January – Researchers in China report the successful transmission of entangled photons between drones, used as nodes for the development of mobile quantum networks or flexible network extensions, marking the first work in which entangled particles were sent between two moving devices.
28 January – Researchers report the development of a highly efficient single-photon source for quantum IT with a system of gated quantum dots in a tunable microcavity which captures photons released from these excited "artificial atoms".
5 February – Researchers demonstrate a first prototype of quantum-logic gates for distributed quantum computers.
13 April – In a preprint, an astronomer describes for the first time how one could search for quantum communication transmissions sent by extraterrestrial intelligence using existing telescope and receiver technology. He also provides arguments for why future searches of SETI should also target interstellar quantum communications.
7 May – Two studies complement research published September 2020 by quantum-entangling two mechanical oscillators.
8 June – A Japanese tech company achieves quantum communications over optical fibres exceeding 600 km in length, a new world record distance.
17 June – Researchers present a two 19-inch rack quantum computing demonstrator, the world's first quality standards-meeting compact quantum computer.
7 July – Researchers present a programmable quantum simulator that can operate with 256 qubits.