The idea of time travel has dazzled sci-fi enthusiasts for years. Science tells us that traveling to the future is technically feasible, at least if you're willing to go near the speed of light, but going back in time is ...
Quantum Physics
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Quantum Physics
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Researchers from MIT and the University of Michigan have discovered a new way to drive chemical reactions that could generate a wide variety of compounds with desirable pharmaceutical properties.
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Quantum computers have the potential to be revolutionary tools for their ability to perform calculations that would take classical computers many years to resolve.
Quantum Physics
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Earth observations are one of the most essential functions of our current fleet of satellites. Typically, each satellite specializes in one kind of remote sensing—monitoring ocean levels, for example, or watching clouds ...
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A new study published in Nature Physics introduces a theory of electron-phonon coupling that is affected by the quantum geometry of the electronic wavefunctions.
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Quantum Physics
Jun 7, 2024
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In quantum physics, a quantum state is a mathematical object that fully describes a quantum system. One typically imagines some experimental apparatus and procedure which "prepares" this quantum state; the mathematical object then reflects the setup of the apparatus. Quantum states can be statistically mixed, corresponding to an experiment involving a random change of the parameters. States obtained in this way are called mixed states, as opposed to pure states, which cannot be described as a mixture of others. When performing a certain measurement on a quantum state, the result generally described by a probability distribution, and the form that this distribution takes is completely determined by the quantum state and the observable describing the measurement. However, unlike in classical mechanics, the result of a measurement on even a pure quantum state is only determined probabilistically. This reflects a core difference between classical and quantum physics.
Mathematically, a pure quantum state is typically represented by a vector in a Hilbert space. In physics, bra-ket notation is often used to denote such vectors. Linear combinations (superpositions) of vectors can describe interference phenomena. Mixed quantum states are described by density matrices.
In a more general mathematical context, quantum states can be understood as positive normalized linear functionals on a C* algebra; see GNS construction.
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