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10−21
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It is worth being explicit about what remained unverified in 1961: Landauer’s paper was a theoretical argument grounded in general reasoning about bistable physical systems, not a measurement. No experiment existed, or could have existed with 1961-era instrumentation, capable of resolving a kBTln2 heat signature from a single erased bit — that quantity, at room temperature, is on the order of 10^{-21} joules, far below the noise floor of any calorimetry available at the time. The principle stood as an unconfirmed but increasingly trusted theoretical result for more than fifty years.
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Equation 7 · Physics
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.
It is worth being explicit about what remained unverified in 1961: Landauer’s paper was a theoretical argument grounded in general reasoning about bistable physical systems, not a measurement. No experiment existed, or could have existed with 1961-era instrumentation, capable of resolving a kBTln2 heat signature from a single erased bit — that quantity, at room temperature, is on the order of 10^{-21} joules, far below the noise floor of any calorimetry available at the time. The principle stood as an unconfirmed but increasingly trusted theoretical result for more than fifty years.
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Article →Equation 16 · Physics
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.
The last major gap in this record closed two years later. Landauer’s 1961 principle had stood for half a century as a trusted but experimentally unconfirmed claim, mainly because dissipating and resolving a heat signal on the order of 10^{-21} joules from a single bit erasure was beyond available calorimetry. Antoine Bérut, Artak Arakelyan, Artyom Petrosyan, Sergio Ciliberto, Raoul Dillenschneider, and Eric Lutz closed that gap in 2012 with “Experimental Verification of Landauer’s Principle Linking Information and Thermodynamics,” published in Nature [ 9 ] . Rather than attempting calorimetry on an electronic bit, they built a colloidal analogue: a single micron-scale bead confined in a…
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Article →Equation 43 · Evolutionary Nuclear Physics
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.
The rate of each step varies by a span that is difficult to convey without sounding like hyperbole, and the chart of nuclides is, among other things, a map of that variation. At the fast extreme, some of the lightest particle-unbound configurations decay in a time too short to be meaningfully called a “half-life” in the ordinary sense — lithium-5, unbound against proton emission, has a tabulated half-life of less than 10^{-21} seconds. At the slow extreme, tellurium-128’s double-beta decay to xenon-128 proceeds with a half-life of 7.7(4)×10^{24} years according to NUBASE2020’s current tabulation, the longest half-life recorded for any nuclide established to be radioactive [ 2 ] . That…
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