{
  "_about": "One row per event. 'era' groups the strip. 'plain' is the one line a reader gets first; 'more' is the paragraph under it. 'qubits' is a count claimed for a machine in that event, used for the chart; leave it out where no machine was announced. 'source' is where the fact can be checked.",
  "events": [
    {"year": 1900, "date": "1900-12-14", "era": "quantum", "title": "Planck's lumps of light",
     "plain": "Max Planck finds that hot things give off light in fixed-size lumps, not a smooth flow. He calls the lump size a quantum.",
     "more": "He was trying to explain the colour of glowing metal and could only make the numbers work by assuming energy came in packets. He thought it was a trick of the math. It was the start of the whole subject.",
     "who": "Max Planck", "source": "https://en.wikipedia.org/wiki/Planck%27s_law", "source_name": "Wikipedia: Planck's law"},
    {"year": 1905, "date": "1905-03", "era": "quantum", "title": "Einstein says light is particles",
     "plain": "Albert Einstein explains why light knocks electrons out of metal: light arrives as particles, later called photons.",
     "more": "This is the paper that won him the Nobel Prize, not relativity. A photon either has enough energy to knock an electron loose or it does not; a dimmer light sends fewer photons, not weaker ones.",
     "who": "Albert Einstein", "source": "https://en.wikipedia.org/wiki/Photoelectric_effect", "source_name": "Wikipedia: Photoelectric effect"},
    {"year": 1913, "date": "1913", "era": "quantum", "title": "Bohr's atom has rungs",
     "plain": "Niels Bohr says an electron in an atom can only sit on certain rungs of energy, and jumps between them by giving off or taking in one photon.",
     "more": "The rungs are why each element has its own colours when heated. Two of those rungs, picked out and controlled, are what a qubit is in most machines today.",
     "who": "Niels Bohr", "source": "https://en.wikipedia.org/wiki/Bohr_model", "source_name": "Wikipedia: Bohr model"},
    {"year": 1924, "date": "1924", "era": "quantum", "title": "Matter is a wave too",
     "plain": "Louis de Broglie says that if light can act like a particle, then particles like electrons act like waves.",
     "more": "Confirmed three years later when electrons fired at a nickel crystal made a ripple pattern. Everything in a quantum computer rests on this: the things inside it are waves, and waves can add up or cancel.",
     "who": "Louis de Broglie", "source": "https://en.wikipedia.org/wiki/Matter_wave", "source_name": "Wikipedia: Matter wave"},
    {"year": 1925, "date": "1925-07", "era": "quantum", "title": "Heisenberg's matrix mechanics",
     "plain": "Werner Heisenberg, 23, works out a set of rules for atoms using tables of numbers. It is the first full version of quantum mechanics.",
     "more": "He did it on the island of Heligoland, sent there by hay fever. The tables were matrices, and the fact that A times B is not B times A in his tables is the same fact behind the uncertainty principle he wrote down two years later.",
     "who": "Werner Heisenberg", "source": "https://en.wikipedia.org/wiki/Matrix_mechanics", "source_name": "Wikipedia: Matrix mechanics"},
    {"year": 1926, "date": "1926", "era": "quantum", "title": "Schrödinger's wave equation",
     "plain": "Erwin Schrödinger writes one equation that says how the wave of a particle changes over time. It is still the equation.",
     "more": "It turned out to give the same answers as Heisenberg's tables. The wave it describes is not a wave of water or sound; its size squared is the chance of finding the particle in a place. That 'size squared' rule is what makes quantum odds different from coin odds.",
     "who": "Erwin Schrödinger", "source": "https://en.wikipedia.org/wiki/Schr%C3%B6dinger_equation", "source_name": "Wikipedia: Schrödinger equation"},
    {"year": 1927, "date": "1927-10", "era": "quantum", "title": "The Solvay fight",
     "plain": "The founders meet in Brussels and argue about what the theory means. Einstein doubts it; Bohr defends it. Nobody settles it.",
     "more": "Heisenberg's uncertainty principle came out the same year: you cannot know both where a particle is and how fast it is going, not because your ruler is bad but because the particle does not have both at once. The Brussels argument is still going on, in a quieter form, in every discussion of what a measurement is.",
     "who": "Solvay Conference", "source": "https://en.wikipedia.org/wiki/Solvay_Conference", "source_name": "Wikipedia: Solvay Conference"},
    {"year": 1935, "date": "1935-05", "era": "quantum", "title": "Einstein's 'spooky' objection",
     "plain": "Einstein, Podolsky and Rosen point out that the theory lets two particles stay linked at any distance. They say this shows the theory is missing something. Schrödinger names the link 'entanglement' the same year, and describes his cat.",
     "more": "Einstein wanted a hidden layer of facts underneath. The linked particles he complained about are the resource every quantum computer runs on. The cat was a joke about the same problem: a cat that is alive and dead until you look is what the math seems to say, and Schrödinger thought that was absurd.",
     "who": "Einstein, Podolsky, Rosen; Schrödinger", "source": "https://en.wikipedia.org/wiki/EPR_paradox", "source_name": "Wikipedia: EPR paradox"},
    {"year": 1936, "date": "1936", "era": "computing", "title": "Turing describes a universal computer",
     "plain": "Alan Turing describes a simple imaginary machine that can do any calculation any other machine can do. Every ordinary computer since is one of these.",
     "more": "A quantum computer is a different kind of machine. It cannot compute anything a Turing machine cannot. It can do some things in far fewer steps.",
     "who": "Alan Turing", "source": "https://en.wikipedia.org/wiki/Turing_machine", "source_name": "Wikipedia: Turing machine"},
    {"year": 1947, "date": "1947-12", "era": "computing", "title": "The transistor",
     "plain": "Bell Labs builds the transistor, the switch that makes every ordinary computer work. It works because of quantum mechanics, but it computes with plain bits.",
     "more": "Worth keeping in mind: the phone in your pocket already runs on quantum physics. What a quantum computer adds is using the wave part of the physics to compute, not only the switching part.",
     "who": "Bardeen, Brattain, Shockley", "source": "https://en.wikipedia.org/wiki/Transistor", "source_name": "Wikipedia: Transistor"},
    {"year": 1948, "date": "1948", "era": "computing", "title": "Shannon names the bit",
     "plain": "Claude Shannon works out how to measure information, and the unit is the bit: one yes or no.",
     "more": "A qubit is what you get when you ask the same question about a quantum system. The answer, worked out over the next fifty years, is that it holds one bit when you read it and something stranger before you do.",
     "who": "Claude Shannon", "source": "https://en.wikipedia.org/wiki/A_Mathematical_Theory_of_Communication", "source_name": "Wikipedia: A Mathematical Theory of Communication"},
    {"year": 1964, "date": "1964", "era": "quantum", "title": "Bell's test",
     "plain": "John Bell shows that Einstein's hidden layer of facts would leave a fingerprint in the numbers, and that quantum mechanics predicts a different fingerprint. So it can be tested.",
     "more": "Bell was a CERN engineer who did this on a sabbatical. His inequality turned a philosophy argument into an experiment. Every test since has come out on the quantum side.",
     "who": "John Stewart Bell", "source": "https://en.wikipedia.org/wiki/Bell%27s_theorem", "source_name": "Wikipedia: Bell's theorem"},
    {"year": 1973, "date": "1973", "era": "computing", "title": "Computing without throwing anything away",
     "plain": "Charles Bennett at IBM shows a computer can run every step backwards as well as forwards and, in principle, use no energy doing it.",
     "more": "Quantum mechanics only allows reversible steps, so this is the bridge. If reversible computing were impossible, quantum computing would be too.",
     "who": "Charles Bennett", "source": "https://en.wikipedia.org/wiki/Reversible_computing", "source_name": "Wikipedia: Reversible computing"},
    {"year": 1980, "date": "1980", "era": "idea", "title": "Benioff's quantum Turing machine",
     "plain": "Paul Benioff writes down a Turing machine that obeys quantum mechanics. It is the first paper to describe a quantum computer, though it computes nothing an ordinary one could not.",
     "more": "Around the same time Yuri Manin in Moscow noted that simulating quantum systems is exponentially hard for ordinary computers and hinted that a quantum machine might do better.",
     "who": "Paul Benioff; Yuri Manin", "source": "https://en.wikipedia.org/wiki/Paul_Benioff", "source_name": "Wikipedia: Paul Benioff"},
    {"year": 1981, "date": "1981-05", "era": "idea", "title": "Feynman: build one",
     "plain": "Richard Feynman tells a conference at MIT that ordinary computers cannot keep up with nature, and that a computer built from quantum parts could. 'Nature isn't classical, dammit.'",
     "more": "The talk, printed in 1982 as 'Simulating Physics with Computers', is the usual starting gun. His point was narrow and still the strongest case for the machine: to model molecules and materials, which are quantum, use something quantum.",
     "who": "Richard Feynman", "source": "https://doi.org/10.1007/BF02650179", "source_name": "Int. J. Theor. Phys. 21, 467 (1982)"},
    {"year": 1982, "date": "1982", "era": "idea", "title": "You cannot copy a qubit",
     "plain": "William Wootters, Wojciech Zurek and Dennis Dieks prove that an unknown quantum state cannot be copied. That rules out the backup trick ordinary computers use against errors.",
     "more": "The same year Alain Aspect's team in Paris ran a Bell test with the settings changed while the photons were in flight. Quantum won again. Aspect shared the 2022 Nobel for it.",
     "who": "Wootters, Zurek, Dieks; Alain Aspect", "source": "https://en.wikipedia.org/wiki/No-cloning_theorem", "source_name": "Wikipedia: No-cloning theorem"},
    {"year": 1984, "date": "1984", "era": "idea", "title": "Quantum keys",
     "plain": "Bennett and Gilles Brassard show two people can share a secret key using photons, and any eavesdropper leaves marks. It is the first quantum technology that does something useful.",
     "more": "Called BB84 after their initials and the year. It is not a computer; it is a way to send keys. It is sold commercially now and runs over fibre and by satellite.",
     "who": "Charles Bennett, Gilles Brassard", "source": "https://en.wikipedia.org/wiki/BB84", "source_name": "Wikipedia: BB84"},
    {"year": 1985, "date": "1985", "era": "idea", "title": "Deutsch's universal quantum computer",
     "plain": "David Deutsch in Oxford describes a quantum computer that can run any quantum program, and gives the first problem it solves faster than a plain computer.",
     "more": "His first problem was a toy: tell whether a coin is fair or double-headed in one flip instead of two. The point was that the speed-up was real at all.",
     "who": "David Deutsch", "source": "https://en.wikipedia.org/wiki/Quantum_Turing_machine", "source_name": "Wikipedia: Quantum Turing machine"},
    {"year": 1993, "date": "1993", "era": "idea", "title": "Teleportation",
     "plain": "Bennett and five others show a qubit's state can be moved from one particle to another far away, using an entangled pair and two ordinary bits. Nothing travels faster than light; the original is destroyed.",
     "more": "Demonstrated with photons in 1997. Today it is a routine step inside quantum networks and some error-correction schemes.",
     "who": "Bennett, Brassard, Crépeau, Jozsa, Peres, Wootters", "source": "https://en.wikipedia.org/wiki/Quantum_teleportation", "source_name": "Wikipedia: Quantum teleportation"},
    {"year": 1994, "date": "1994", "era": "idea", "title": "Shor's algorithm",
     "plain": "Peter Shor at Bell Labs finds that a big enough quantum computer could break the codes that protect bank transfers and the web, by finding the prime factors of large numbers quickly.",
     "more": "This is the moment governments and companies started paying. Ordinary computers take longer than the age of the universe on the numbers used in practice; Shor's method takes hours on a machine that does not yet exist. It also drove the new codes that NIST standardised in 2024.",
     "who": "Peter Shor", "source": "https://en.wikipedia.org/wiki/Shor%27s_algorithm", "source_name": "Wikipedia: Shor's algorithm"},
    {"year": 1995, "date": "1995", "era": "idea", "title": "Errors can be fixed after all",
     "plain": "Shor shows that spreading one qubit across nine lets you catch and fix errors without reading the qubit. Andrew Steane finds a seven-qubit version. The no-copying rule had made people think this was impossible.",
     "more": "The same year Ignacio Cirac and Peter Zoller propose a way to build gates with trapped ions, and in December Chris Monroe and David Wineland's group at NIST runs the first two-qubit gate on a single trapped beryllium ion.",
     "who": "Peter Shor; Andrew Steane; Cirac & Zoller; Monroe & Wineland", "qubits": 1, "machine": "NIST ion trap", "source": "https://en.wikipedia.org/wiki/Quantum_error_correction", "source_name": "Wikipedia: Quantum error correction"},
    {"year": 1996, "date": "1996", "era": "idea", "title": "Grover's search",
     "plain": "Lov Grover shows a quantum computer can find one item in an unsorted list of a million by checking about a thousand times, where a plain computer needs about half a million.",
     "more": "A square-root speed-up, not the giant one Shor gets. It works on almost any search problem, which is why it comes up so often. The same year Seth Lloyd showed Feynman was right: a quantum computer can simulate any quantum system efficiently.",
     "who": "Lov Grover; Seth Lloyd", "source": "https://en.wikipedia.org/wiki/Grover%27s_algorithm", "source_name": "Wikipedia: Grover's algorithm"},
    {"year": 1997, "date": "1997", "era": "idea", "title": "The threshold theorem",
     "plain": "Several groups prove that if each part of the machine errs less than some fixed rate, error correction can push the total error as low as you like. Below the line, bigger machines get better instead of worse.",
     "more": "Dorit Aharonov and Michael Ben-Or, Alexei Kitaev, and Knill, Laflamme and Zurek got there separately. Kitaev also proposed the toric code, the ancestor of the surface code that the leading machines use today. The whole field since is an effort to get under that line.",
     "who": "Aharonov & Ben-Or; Kitaev; Knill, Laflamme & Zurek", "source": "https://en.wikipedia.org/wiki/Quantum_threshold_theorem", "source_name": "Wikipedia: Quantum threshold theorem"},
    {"year": 1998, "date": "1998", "era": "build", "title": "Two qubits in a test tube",
     "plain": "Isaac Chuang, Neil Gershenfeld and Mark Kubinec run Deutsch's toy problem on the nuclei of chloroform molecules in a liquid, using a hospital-style magnetic resonance machine.",
     "more": "The same year Bruce Kane proposed building qubits from single phosphorus atoms in silicon, the plan Australian groups still follow.",
     "who": "Chuang, Gershenfeld, Kubinec", "qubits": 2, "machine": "NMR, chloroform", "source": "https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_quantum_computer", "source_name": "Wikipedia: NMR quantum computer"},
    {"year": 1999, "date": "1999-04", "era": "build", "title": "A qubit made of wire",
     "plain": "Yasunobu Nakamura's group at NEC in Japan shows a tiny superconducting circuit, a loop of metal with no resistance, can act as a qubit for a few billionths of a second.",
     "more": "This is the ancestor of the chips at Google and IBM. It is a circuit you can print, which is why it won.",
     "who": "Nakamura, Pashkin, Tsai", "qubits": 1, "machine": "NEC charge qubit", "source": "https://www.nature.com/articles/19718", "source_name": "Nature 398, 786 (1999)"},
    {"year": 2000, "date": "2000", "era": "build", "title": "DiVincenzo's checklist",
     "plain": "David DiVincenzo at IBM writes the five things any quantum computer must have. It is still the checklist.",
     "more": "Qubits you can add more of; a way to set them to zero; long enough before they lose their state; a full set of gates; and a way to read them out.",
     "who": "David DiVincenzo", "source": "https://en.wikipedia.org/wiki/DiVincenzo%27s_criteria", "source_name": "Wikipedia: DiVincenzo's criteria"},
    {"year": 2001, "date": "2001-12", "era": "build", "title": "15 = 3 × 5",
     "plain": "IBM and Stanford run Shor's algorithm on seven qubits in a molecule and factor 15. It is the smallest number that counts, and it took a room of equipment.",
     "more": "The same year Knill, Laflamme and Milburn showed that photons, mirrors and detectors alone could make a universal quantum computer, the root of today's photonic companies.",
     "who": "Vandersypen, Chuang and others", "qubits": 7, "machine": "NMR, IBM Almaden", "source": "https://www.nature.com/articles/414883a", "source_name": "Nature 414, 883 (2001)"},
    {"year": 2007, "date": "2007", "era": "build", "title": "The transmon",
     "plain": "Yale's group designs the transmon, a superconducting qubit that ignores most electrical noise. Nearly every superconducting chip since uses it.",
     "more": "Also 2007: D-Wave in Canada shows a 16-qubit machine of a different kind, an annealer, that settles into a low-energy answer rather than running gates. Whether it beats ordinary computers is still argued.",
     "who": "Koch, Schoelkopf, Devoret and others; D-Wave", "qubits": 16, "machine": "D-Wave Orion", "source": "https://en.wikipedia.org/wiki/Transmon", "source_name": "Wikipedia: Transmon"},
    {"year": 2011, "date": "2011-05", "era": "build", "title": "First quantum computer sold",
     "plain": "Lockheed Martin buys a D-Wave One, 128 qubits, for about ten million dollars. It is an annealer, not a gate machine, and the physics community argues about what it does.",
     "more": "Ten years of that argument taught the field how to benchmark. The short version: D-Wave machines are quantum, and no one has shown one beating the best ordinary method on a practical problem.",
     "who": "D-Wave, Lockheed Martin", "qubits": 128, "machine": "D-Wave One", "source": "https://en.wikipedia.org/wiki/D-Wave_Systems", "source_name": "Wikipedia: D-Wave Systems"},
    {"year": 2012, "date": "2012-10", "era": "build", "title": "Nobel for handling single particles",
     "plain": "Serge Haroche and David Wineland win the Nobel Prize for measuring and controlling single atoms and photons without wrecking them. That is the lab skill quantum computers need.",
     "more": "The same year Austin Fowler and others laid out the surface code in a form engineers could build: a checkerboard of qubits where neighbours check each other, tolerating about one error in a hundred.",
     "who": "Haroche, Wineland; Fowler and others", "source": "https://www.nobelprize.org/prizes/physics/2012/summary/", "source_name": "Nobel Prize 2012"},
    {"year": 2016, "date": "2016-05", "era": "build", "title": "A quantum computer on the web",
     "plain": "IBM puts a five-qubit chip online for anyone to program. Within a year students and hobbyists had run hundreds of thousands of jobs on it.",
     "more": "This is when the machine stopped being a lab instrument and became a thing people could try. Most of what a beginner learns today is learned this way.",
     "who": "IBM", "qubits": 5, "machine": "IBM Quantum Experience", "source": "https://en.wikipedia.org/wiki/IBM_Quantum_Platform", "source_name": "Wikipedia: IBM Quantum Platform"},
    {"year": 2019, "date": "2019-10-23", "era": "build", "title": "Google's Sycamore",
     "plain": "Google's 53-qubit chip does a contrived random-sampling task in 200 seconds that Google says would take a supercomputer 10,000 years. IBM says two and a half days. Either way the gap is real, and the task is useless.",
     "more": "Called 'quantum supremacy'. The word and the claim were both argued over. Better ordinary methods later narrowed the gap on this exact task, which is the normal pattern: each claim of advantage moves the target.",
     "who": "Google Quantum AI", "qubits": 53, "machine": "Sycamore", "source": "https://www.nature.com/articles/s41586-019-1666-5", "source_name": "Nature 574, 505 (2019)"},
    {"year": 2020, "date": "2020-12", "era": "build", "title": "Jiuzhang, with light",
     "plain": "A team at USTC in Hefei does a different sampling task with photons, and claims a bigger gap than Google's.",
     "more": "Jiuzhang is not programmable in the general sense; it does one task. It showed China was in the race with a different technology.",
     "who": "USTC, Pan Jianwei's group", "source": "https://www.science.org/doi/10.1126/science.abe8770", "source_name": "Science 370, 1460 (2020)"},
    {"year": 2021, "date": "2021-11", "era": "build", "title": "IBM Eagle: 127 qubits",
     "plain": "IBM's Eagle chip passes 100 qubits. The qubits are noisy, and the count alone means little, but the count was the headline.",
     "more": "The same year USTC's Zuchongzhi 2 (66 superconducting qubits) repeated Google's task with a bigger claimed gap.",
     "who": "IBM", "qubits": 127, "machine": "Eagle", "source": "https://www.ibm.com/quantum/blog/127-qubit-quantum-processor-eagle", "source_name": "IBM Research blog"},
    {"year": 2022, "date": "2022-10-04", "era": "build", "title": "Nobel for Bell tests",
     "plain": "Alain Aspect, John Clauser and Anton Zeilinger win the Nobel Prize for the experiments that showed entanglement is real and Einstein's hidden layer is not there.",
     "more": "Clauser did the first test in 1972 with equipment he built himself; his advisers told him it was a waste of time. IBM's 433-qubit Osprey arrived in November.",
     "who": "Aspect, Clauser, Zeilinger", "qubits": 433, "machine": "IBM Osprey", "source": "https://www.nobelprize.org/prizes/physics/2022/summary/", "source_name": "Nobel Prize 2022"},
    {"year": 2023, "date": "2023-02", "era": "correct", "title": "Bigger gets better, a little",
     "plain": "Google shows a surface code with 49 qubits errs slightly less than one with 17. It is the first time in a real machine that adding qubits reduced the error instead of adding to it.",
     "more": "The gain was small and the paper said so. It mattered because it was the first sign of being under the threshold line from 1997.",
     "who": "Google Quantum AI", "source": "https://www.nature.com/articles/s41586-022-05434-1", "source_name": "Nature 614, 676 (2023)"},
    {"year": 2023, "date": "2023-12-06", "era": "correct", "title": "48 logical qubits from atoms",
     "plain": "A Harvard, MIT and QuEra team uses 280 atoms held by laser beams to make 48 error-corrected 'logical' qubits and run small programs on them.",
     "more": "A logical qubit is a group of physical qubits acting as one reliable qubit. Two days earlier IBM had shown its 1,121-qubit Condor chip and its smaller, cleaner Heron. The field's attention was moving from counts to quality.",
     "who": "Harvard, MIT, QuEra", "qubits": 1121, "machine": "IBM Condor", "source": "https://www.nature.com/articles/s41586-023-06927-3", "source_name": "Nature 626, 58 (2024)"},
    {"year": 2024, "date": "2024-04", "era": "correct", "title": "Logical qubits that beat their parts",
     "plain": "Microsoft and Quantinuum make four logical qubits from 30 trapped ions that err 800 times less often than the raw ions.",
     "more": "In August NIST published the first three post-quantum encryption standards (FIPS 203, 204, 205), the replacement locks for the ones Shor's algorithm would pick.",
     "who": "Microsoft, Quantinuum; NIST", "source": "https://azure.microsoft.com/en-us/blog/quantum/2024/04/03/how-microsoft-and-quantinuum-achieved-reliable-quantum-computing/", "source_name": "Microsoft Azure blog"},
    {"year": 2024, "date": "2024-12-09", "era": "correct", "title": "Google Willow: under the line",
     "plain": "Google's Willow chip shows the error rate halving each time the code grows from 3×3 to 5×5 to 7×7 qubits. That is the threshold theorem working in hardware.",
     "more": "Willow has 105 qubits. The headline claim about a task taking 'ten septillion years' on a supercomputer was the same kind of contrived sampling task as 2019. The error-correction result is the one that matters.",
     "who": "Google Quantum AI", "qubits": 105, "machine": "Willow", "source": "https://www.nature.com/articles/s41586-024-08449-y", "source_name": "Nature 638, 920 (2025)"}
  ]
}