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Some physicists, such as Lawrence Krauss, Stephen Hawking or Alexander Vilenkin, call or called this state "a universe from nothingness", although the zero-energy universe model requires both a matter field with positive energy and a gravitational field with negative energy to exist. [2] The hypothesis is broadly discussed in popular sources.
The forgetting curve hypothesizes the decline of memory retention in time. This curve shows how information is lost over time when there is no attempt to retain it. [1] A related concept is the strength of memory that refers to the durability that memory traces in the brain. The stronger the memory, the longer period of time that a person is ...
An external-time energy–time uncertainty principle might say that measuring the energy of a quantum system to an accuracy requires a time interval > /. [38] However, Yakir Aharonov and David Bohm [ 46 ] [ 36 ] have shown that, in some quantum systems, energy can be measured accurately within an arbitrarily short time: external-time ...
The uncertainty principle states the uncertainty in energy and time can be related by [4] , where 1 / 2 ħ ≈ 5.272 86 × 10 −35 J⋅s. This means that pairs of virtual particles with energy Δ E {\displaystyle \Delta E} and lifetime shorter than Δ t {\displaystyle \Delta t} are continually created and annihilated in empty space.
The concept of the Void has its origins in ancient Greek philosophy, where it was central to discussions on the nature of the cosmos and space. Parmenides suggested it did not exist and used this to argue for the non-existence of change, motion, and differentiation, among other things. [2]
The Gödel metric, also known as the Gödel solution or Gödel universe, is an exact solution, found in 1949 by Kurt Gödel, [1] of the Einstein field equations in which the stress–energy tensor contains two terms: the first representing the matter density of a homogeneous distribution of swirling dust particles (see dust solution), and the second associated with a negative cosmological ...
This question has been written about by philosophers since at least the ancient Parmenides (c. 515 BC). [1] [2]"Why is there anything at all?" or "Why is there something rather than nothing?" is a question about the reason for basic existence which has been raised or commented on by a range of philosophers and physicists, including Gottfried Wilhelm Leibniz, [3] Ludwig Wittgenstein, [4] and ...
Imaginary time is a mathematical representation of time that appears in some approaches to special relativity and quantum mechanics. It finds uses in certain cosmological theories. Mathematically, imaginary time is real time which has undergone a Wick rotation so that its coordinates are multiplied by the imaginary unit i .