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Popper's Experiment
Popper's experiment is an experiment proposed by the philosopher Karl Popper to put to the test different interpretations of quantum mechanics (QM). In fact, as early as 1934, Popper started criticising the increasingly more accepted Copenhagen interpretation, a popular subjectivist interpretation of quantum mechanics. Therefore, in his most famous book ''Logik der Forschung'' he proposed a first experiment alleged to empirically discriminate between the Copenhagen Interpretation and a realist interpretation, which he advocated. Einstein, however, wrote a letter to Popper about the experiment in which he raised some crucial objections and Popper himself declared that this first attempt was "a gross mistake for which I have been deeply sorry and ashamed of ever since". Popper, however, came back to the foundations of quantum mechanics from 1948, when he developed his criticism of determinism in both quantum and classical physics. As a matter of fact, Popper greatly intensified his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Popper
Sir Karl Raimund Popper (28 July 1902 – 17 September 1994) was an Austrian-British philosopher, academic and social commentator. One of the 20th century's most influential philosophers of science, Popper is known for his rejection of the classical inductivist views on the scientific method in favour of empirical falsification. According to Popper, a theory in the empirical sciences can never be proven, but it can be falsified, meaning that it can (and should) be scrutinised with decisive experiments. Popper was opposed to the classical justificationist account of knowledge, which he replaced with critical rationalism, namely "the first non-justificational philosophy of criticism in the history of philosophy". In political discourse, he is known for his vigorous defence of liberal democracy and the principles of social criticism that he believed made a flourishing open society possible. His political philosophy embraced ideas from major democratic political ideologies, inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Measurement
In quantum physics, a measurement is the testing or manipulation of a physical system to yield a numerical result. The predictions that quantum physics makes are in general probabilistic. The mathematical tools for making predictions about what measurement outcomes may occur were developed during the 20th century and make use of linear algebra and functional analysis. Quantum physics has proven to be an empirical success and to have wide-ranging applicability. However, on a more philosophical level, debates continue about the meaning of the measurement concept. Mathematical formalism "Observables" as self-adjoint operators In quantum mechanics, each physical system is associated with a Hilbert space, each element of which represents a possible state of the physical system. The approach codified by John von Neumann represents a measurement upon a physical system by a self-adjoint operator on that Hilbert space termed an "observable". These observables play the role of measurab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loopholes In Bell Test Experiments
A Bell test, also known as Bell inequality test or Bell experiment, is a real-world physics experiment designed to test the theory of quantum mechanics in relation to Albert Einstein's concept of local realism. Named for John Stewart Bell, the experiments test whether or not the real world satisfies local realism, which requires the presence of some additional local variables (called "hidden" because they are not a feature of quantum theory) to explain the behavior of particles like photons and electrons. To date, all Bell tests have found that the hypothesis of local hidden variables is inconsistent with the way that physical systems behave. According to Bell's theorem, if nature actually operates in accord with any theory of local hidden variables, then the results of a Bell test will be constrained in a particular, quantifiable way. If a Bell experiment is performed and the results are ''not'' thus constrained, then the hypothesized local hidden variables cannot exist. Such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conditional Distribution
In probability theory and statistics, given two jointly distributed random variables X and Y, the conditional probability distribution of Y given X is the probability distribution of Y when X is known to be a particular value; in some cases the conditional probabilities may be expressed as functions containing the unspecified value x of X as a parameter. When both X and Y are categorical variables, a conditional probability table is typically used to represent the conditional probability. The conditional distribution contrasts with the marginal distribution of a random variable, which is its distribution without reference to the value of the other variable. If the conditional distribution of Y given X is a continuous distribution, then its probability density function is known as the conditional density function. The properties of a conditional distribution, such as the moments, are often referred to by corresponding names such as the conditional mean and conditional variance. Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
No-communication Theorem
In physics, the no-communication theorem or no-signaling principle is a no-go theorem from quantum information theory which states that, during measurement of an entangled quantum state, it is not possible for one observer, by making a measurement of a subsystem of the total state, to communicate information to another observer. The theorem is important because, in quantum mechanics, quantum entanglement is an effect by which certain widely separated events can be correlated in ways that, at first glance, suggest the possibility of communication faster-than-light. The no-communication theorem gives conditions under which such transfer of information between two observers is impossible. These results can be applied to understand the so-called paradoxes in quantum mechanics, such as the EPR paradox, or violations of local realism obtained in tests of Bell's theorem. In these experiments, the no-communication theorem shows that failure of local realism does not lead to what could ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superluminal Communication
Superluminal communication is a hypothetical process in which information is sent at faster-than-light (FTL) speeds. The current scientific consensus is that faster-than-light communication is not possible, and to date it has not been achieved in any experiment. Superluminal communication other than possibly through wormholes is likely impossible because, in a Lorentz-invariant theory, it could be used to transmit information into the past. This complicates causality, but no theoretical arguments conclusively preclude this possibility. A number of theories and phenomena related to superluminal communication have been proposed or studied, including tachyons, neutrinos, quantum nonlocality, wormholes, and quantum tunneling. Proposed mechanisms Tachyons Tachyonic particles are hypothetical particles that travel faster than light. These would allow superluminal communication, and for this reason are widely believed not to exist. By contrast, tachyonic fields quantum fields with ima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ghost Interference
A ghost is the soul or spirit of a dead person or animal that is believed to be able to appear to the living. In ghostlore, descriptions of ghosts vary widely from an invisible presence to translucent or barely visible wispy shapes, to realistic, lifelike forms. The deliberate attempt to contact the spirit of a deceased person is known as necromancy, or in spiritism as a ''séance''. Other terms associated with it are apparition, haunt, phantom, poltergeist, shade, specter or spectre, spirit, spook, wraith, demon, and ghoul. The belief in the existence of an afterlife, as well as manifestations of the spirits of the dead, is widespread, dating back to animism or ancestor worship in pre-literate cultures. Certain religious practices—funeral rites, exorcisms, and some practices of spiritualism and ritual magic—are specifically designed to rest the spirits of the dead. Ghosts are generally described as solitary, human-like essences, though stories of ghostly armies and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Path Integral Formulation
The path integral formulation is a description in quantum mechanics that generalizes the action principle of classical mechanics. It replaces the classical notion of a single, unique classical trajectory for a system with a sum, or functional integral, over an infinity of quantum-mechanically possible trajectories to compute a quantum amplitude. This formulation has proven crucial to the subsequent development of theoretical physics, because manifest Lorentz covariance (time and space components of quantities enter equations in the same way) is easier to achieve than in the operator formalism of canonical quantization. Unlike previous methods, the path integral allows one to easily change coordinates between very different canonical descriptions of the same quantum system. Another advantage is that it is in practice easier to guess the correct form of the Lagrangian of a theory, which naturally enters the path integrals (for interactions of a certain type, these are ''coordinat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EPR Paradox
EPR may refer to: Science and technology * EPR (nuclear reactor), European Pressurised-Water Reactor * EPR paradox (Einstein–Podolsky–Rosen paradox), in physics * Earth potential rise, in electrical engineering * East Pacific Rise, a mid-oceanic ridge * Electron paramagnetic resonance * Engine pressure ratio,of a jet engine * Ethylene propylene rubber * Yevpatoria RT-70 radio telescope (Evpatoria planetary radar) * Bernays–Schönfinkel class or effectively propositional, in mathematical logic * Endpoint references in Web addressing * Ethnic Power Relations, dataset of ethnic groups * ePrivacy Regulation (ePR), proposal for the regulation of various privacy-related topics, mostly in relation to electronic communications within the European Union Medicine * Enhanced permeability and retention effect, a controversial concept in cancer research * Emergency Preservation and Resuscitation, a medical procedure * Electronic patient record Environment * UNECE Environmental Perform ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
