Quantum machine naked eye." Quantum machine A quantum machine is a human-made device whose collective motion follows the laws of quantum mechanics. The idea that macroscopic objects may follow the laws of quantum mechanics dates back to the advent of quantum mechanics in the early 20th century. However, as highlighted by the Schrödinger's cat thought experiment, quantum effects are not readily observable in large-scale objects. Consequently, quantum states of motion have only been observed in special circumstances at extremely low temperatures. The fragility of quantum effects in macroscopic objects may arise from rapid quantum decoherence. Researchers created the first quantum machine in
Expectation value (quantum mechanics) general case, its spectrum will neither be entirely discrete nor entirely continuous. Still, one can write formula_1 in a spectral decomposition, with a projector-valued measure formula_30. For the expectation value of formula_1 in a pure state formula_48, this means which may be seen as a common generalization of formulas (2) and (4) above. In non-relativistic theories of finitely many particles (quantum mechanics, in the strict sense), the states considered are generally normal. However, in other areas of quantum theory, also non-normal states are in use: They appear, for example. in the form of KMS states in quantum statistical mechanics of