Quantum Mechanics

Extracted Attributes

• Field

  Physics

• Scope

  Describes behavior of matter and light at atomic and subatomic scales

• Key Concepts

  Quantized energy levels, Wave-particle duality, Uncertainty principle, Wave function, Schrödinger's Cat Paradox

• Mathematical Formalism

  Wave function (probability amplitudes)

• Primary Application Scale

  Submicroscopic (atomic and subatomic scales)

• Exhibits Macroscopic Effects

  Superfluidity, Superconductivity, Fractional quantum Hall effect

• Relationship to Classical Physics

  Classical mechanics is an approximation valid at ordinary scales; QM describes systems classical physics cannot

Timeline

• Max Planck provided a solution to the black-body radiation problem, marking an early attempt to understand microscopic phenomena. (Source: Wikipedia)

  1900-XX-XX

• Albert Einstein published a paper explaining the photoelectric effect, further contributing to the 'old quantum theory'. (Source: Wikipedia)

  1905-XX-XX

• The full development of modern quantum mechanics occurred, led by scientists such as Niels Bohr, Erwin Schrödinger, Werner Heisenberg, Max Born, and Paul Dirac. (Source: Wikipedia)

  1925-XX-XX

• John Martinis published his landmark paper on macroscopic quantum mechanics, experimentally demonstrating quantum phenomena like quantum tunneling in an electrical circuit, laying the foundation for quantum computing. (Source: Related Documents)

  1985-XX-XX

• John Martinis's team at Google's quantum lab in Santa Barbara achieved Quantum Supremacy. (Source: Related Documents)

  2019-XX-XX

• John Martinis is recognized as the 2025 winner of the Nobel Prize in Physics for his contributions to quantum mechanics and quantum computing. (Source: Related Documents)

  2025-XX-XX

Quantum mechanics

Quantum mechanics is the fundamental physical theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. It is the foundation of all quantum physics, which includes quantum chemistry, quantum biology, quantum field theory, quantum technology, and quantum information science. Quantum mechanics can describe many systems that classical physics cannot. Classical physics can describe many aspects of nature at an ordinary (macroscopic and (optical) microscopic) scale, but is not sufficient for describing them at very small submicroscopic (atomic and subatomic) scales. Classical mechanics can be derived from quantum mechanics as an approximation that is valid at ordinary scales. Quantum systems have bound states that are quantized to discrete values of energy, momentum, angular momentum, and other quantities, in contrast to classical systems where these quantities can be measured continuously. Measurements of quantum systems show characteristics of both particles and waves (wave–particle duality), and there are limits to how accurately the value of a physical quantity can be predicted prior to its measurement, given a complete set of initial conditions (the uncertainty principle). Quantum mechanics arose gradually from theories to explain observations that could not be reconciled with classical physics, such as Max Planck's solution in 1900 to the black-body radiation problem, and the correspondence between energy and frequency in Albert Einstein's 1905 paper, which explained the photoelectric effect. These early attempts to understand microscopic phenomena, now known as the "old quantum theory", led to the full development of quantum mechanics in the mid-1920s by Niels Bohr, Erwin Schrödinger, Werner Heisenberg, Max Born, Paul Dirac and others. The modern theory is formulated in various specially developed mathematical formalisms. In one of them, a mathematical entity called the wave function provides information, in the form of probability amplitudes, about what measurements of a particle's energy, momentum, and other physical properties may yield.

Web Search Results

• DOE Explains...Quantum Mechanics - Department of Energy

  Quantum mechanics is the field of physics that explains how extremely small objects simultaneously have the characteristics of both particles (tiny pieces of matter) and waves (a disturbance or variation that transfers energy). Physicists call this the “wave-particle duality.” [...] The world of quantum mechanics is very different from how we usually see our macroscopic world, which is controlled by what physicists call classical mechanics. Quantum mechanics grew out of the tremendous progress that physicists made in the early 20th century toward understanding the microscopic world around us and how it differed from the macroscopic world. [...] At the same time, tiny quantized particles such as electrons can also be described as waves. Like a wave in the ocean in our macroscopic world – the world we can see with our eyes -- waves in the quantum world are constantly shifting. In quantum mechanics, scientists talk about a particle’s “wave function.” This is a mathematical representation used to describe the probability that a particle exists at a certain location at a certain time with a certain momentum.

• [PDF] Applications of Quantum Mechanics - DAMTP

  – 6 – 0. Introduction Without wishing to overstate the case, the discovery of quantum mechanics is the single greatest achievement in the history of human civilisation. Quantum mechanics is an outrageous departure from our classical, comforting, com-mon sense view of the world. It is more baffling and disturbing than anything dreamt up by science fiction writers.

• Applications of quantum mechanics - Wikipedia

  Quantum physics is a branch of modern physics in which energy and matter are described at their most fundamental level, that of energy quanta "Quantization (physics)"), elementary particles, and quantum fields. Quantum physics encompasses any discipline concerned with systems that exhibit notable quantum-mechanical effects, where waves have properties of particles, and particles behave like waves. Applications of quantum mechanics include explaining phenomena found in nature as well as [...] Quantum mechanics is also critically important for understanding how individual atoms are joined by covalent bonds to form molecules. The application of quantum mechanics to chemistry is known as quantum chemistry. Quantum mechanics can also provide quantitative insight into ionic and covalent bonding processes by explicitly showing which molecules are energetically favorable to which others and the magnitudes of the energies involved. [...] While quantum mechanics primarily applies to the smaller atomic regimes of matter and energy, some systems exhibit quantum mechanical effects on a large scale. Superfluidity, the frictionless flow of a liquid at temperatures near absolute zero, is one well-known example. So is the closely related phenomenon of superconductivity, the frictionless flow of an electron gas in a conducting material (an electric current) at sufficiently low temperatures. The fractional quantum Hall effect is a

• Real Life Applications of Quantum Mechanics - GeeksforGeeks

  Atomic Structure: Quantum mechanics describes the behavior of electrons in atoms, including their energy levels, orbitals, and spin states. The Schrödinger equation, a fundamental equation of quantum mechanics, is used to calculate the wavefunctions of electrons in atoms, leading to a detailed understanding of atomic structure and the periodic table. [...] Nanoelectronics: Quantum mechanics is essential for understanding and engineering nanoelectronic devices, such as nanoscale transistors, diodes, and quantum wells. Quantum mechanical effects, such as tunneling, ballistic transport, and quantum confinement, become dominant at the nanoscale and are exploited to create novel electronic devices with enhanced performance and functionality. Quantum mechanical simulations and modeling are used to design and optimize nanoelectronic devices, predict [...] Spectroscopy: Quantum mechanics is essential for interpreting spectroscopic data and understanding the interaction of matter with electromagnetic radiation. Quantum mechanical models are used to calculate molecular energy levels, transition probabilities, and spectral lines observed in various spectroscopic techniques, such as infrared spectroscopy, UV-visible spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. ## Application of Quantum Mechanics in nanotechnology

• Introduction to quantum mechanics - Wikipedia

  Quantum mechanics helps people understand chemistry, because it explains how atoms interact with each other and form molecules. Many remarkable phenomena can be explained using quantum mechanics, like superfluidity. For example, if liquid helium cooled to a temperature near absolute zero is placed in a container, it spontaneously flows up and over the rim of its container; this is an effect which cannot be explained by classical physics. ## History [edit] [...] and predicts its spectral energies (corresponding to pure colors), and the intensities "Intensity (physics)") of its light beams. A single photon is a quantum, or smallest observable particle, of the electromagnetic field. A partial photon is never experimentally observed. More broadly, quantum mechanics shows that many properties of objects, such as position, speed, and angular momentum, that appeared continuous in the zoomed-out view of classical mechanics, turn out to be (in the very tiny, [...] > Sometimes we distinguish between quantum mechanics (QM) and quantum field theory (QFT). QM refers to a system in which the number of particles is fixed, and the fields (such as the electromechanical field) are continuous classical entities. QFT ... goes a step further and allows for the creation and annihilation of particles ... He added, however, that quantum mechanics is often used to refer to "the entire notion of quantum view".: 108

• Instance Of

  Q838795