Macroscopic Quantum Mechanics

Extracted Attributes

• Impact

  Expanded understanding of Quantum Mechanics, influenced developments like Peter Shaw's Factoring Algorithm

• Definition

  Quantum phenomena occurring at a macroscopic scale, observable to the human eye, rather than at the atomic level.

• Observed in

  Superfluid helium, Superconductors, Dilute quantum gases, Polaritons, Laser light (referred to as 'quantum fluids')

• Key Examples

  Superfluidity, Superconductivity, Quantum Hall effect, Josephson effect, Topological order, Quantum Tunneling

• Characteristics

  Quantum states occupied by a large number of particles (order of Avogadro number) or quantum states macroscopic in size (up to kilometer-sized in superconducting wires).

• Key 1985 Experiment

  Demonstrated quantum tunneling in a macroscopic electrical circuit built with Superconductors and a Josephson Junction

• Nobel Prizes in Physics

  7 (as of 2025) for work related to macroscopic quantum phenomena

• Advisor for 1985 Experiment

  John Clark

• Location of 1985 Experiment

  UC Berkeley

• Inspiration for 1985 Experiment

  Anthony Leggett, Richard Feynman

• Experimental Foundation for Quantum Computing

  Laid by John Martinis's 1985 experiment

Timeline

• Erwin Schrödinger received the Nobel Prize in Physics. (Source: Web Search)

  1933

• Erwin Schrödinger proposed the Schrödinger's Cat Paradox, illustrating the absurdity of applying quantum mechanics beyond its original realm. (Source: Web Search)

  1935

• John Martinis published his landmark paper on macroscopic quantum mechanics and conducted an experiment demonstrating quantum tunneling in a macroscopic electrical circuit, laying the experimental foundation for quantum computing. (Source: Summary, Related Documents)

  1985-XX-XX

• Extensive experimental work began on quantum gases, particularly Bose–Einstein condensates. (Source: Summary, Wikipedia)

  2000-XX-XX

• John Martinis's team at Google achieved Quantum Supremacy. (Source: Related Documents)

  2019-XX-XX

• John Martinis is the winner of the Nobel Prize in Physics for his work related to macroscopic quantum phenomena. (Source: Summary, Related Documents)

  2025-XX-XX

Macroscopic quantum phenomena

Macroscopic quantum phenomena are processes showing quantum behaviour at the macroscopic scale, rather than at the atomic scale where quantum effects are prevalent. The best-known examples of macroscopic quantum phenomena are superfluidity and superconductivity; other examples include the quantum Hall effect, Josephson effect and topological order. Since 2000 there has been extensive experimental work on quantum gases, particularly Bose–Einstein condensates. As of 2025, seven Nobel Prizes in Physics have been awarded for work related to macroscopic quantum phenomena. Macroscopic quantum phenomena can be observed in superfluid helium and in superconductors, but also in dilute quantum gases, dressed photons such as polaritons and in laser light. Although these media are very different, they are all similar in that they show macroscopic quantum behaviour, and in this respect they all can be referred to as quantum fluids. Quantum phenomena are generally classified as macroscopic when the quantum states are occupied by a large number of particles (of the order of the Avogadro number) or the quantum states involved are macroscopic in size (up to kilometre-sized in superconducting wires).

Web Search Results

• Macroscopic Quantum Mechanics - Annenberg Learner

  The fundamentals of quantum mechanics that we met in Unit 5 characteristically appear on microscopic scales. Macroscopic quantum systems in which liquids, or electric currents, flow without friction or resistance have been known since the early part of the previous century: these are the superfluids and superconductors of traditional condensed matter physics that are discussed in Unit 8. In this unit we focus on an entirely new state of matter only recently created in the laboratory: this is [...] Quantum mechanics provides a useful description of nature at the atomic and subatomic scale, but it also manifests itself in phenomena at macroscopic scales, including lasers, clouds of ultra-cold atoms, superfluids, and superconductivity. Among these phenomena, the recent discovery of new kinds of high-temperature superconducting materials holds the promise of many practical applications—but there is still no theory about how these materials work. See how researchers are approaching this [...] macroscopic A macroscopic object, as opposed to a microscopic one, is large enough to be seen with the unaided eye. Often (but not always), classical physics is adequate to describe macroscopic objects, and a quantum mechanical description is unnecessary. magnetic moment

• Macroscopic quantum phenomena - Wikipedia

  ## Mechanical systems [edit] Macroscopic quantum effects have been observed in the motion of engineered mechanical objects. Research in the field of quantum optomechanics focuses on the manipulation of the quantized vibrational states (phonons) of mechanical resonators. [...] Macroscopic quantum phenomena are processes showing quantum behaviour at the macroscopic scale, rather than at the atomic scale where quantum effects are prevalent. The best-known examples of macroscopic quantum phenomena are superfluidity and superconductivity; other examples include the quantum Hall effect, Josephson effect and topological order. Since 2000 there has been extensive experimental work on quantum gases, particularly Bose–Einstein condensates. [...] Quantum phenomena are generally classified as macroscopic when the quantum states are occupied by a large number of particles (of the order of the Avogadro number) or the quantum states involved are macroscopic in size (up to kilometre-sized in superconducting wires). ## Consequences of the macroscopic occupation [edit]

• About Quantum Mechanics at macroscopic level

  LIGO is an example where quantum mechanics matters on a macroscopic scale. LIGO measures gravitational waves. These waves stretch and squeeze distances as they pass through Earth. The changes are tiny - 1/10,000th the diameter of a proton. Learning how to build a detector sufficiently sensitive took 20 years. [...] I put this comment here, but it is my "reaction" to your comment on F. Zwarts answer: It is entirely unclear what your friend means by saying "QM has no role on the macroscopic level". Indeed, everything is quantum by nature. The macroscopic physics can be understood as emerging from QM in the same way Newton's theory of gravitation emerges from General Relativity. There aren't "two distinct types of theories describing the world" (this is the way I understand your friend's position). The [...] Similarly, QM in the limit of macroscopic objects, results in classic theory. So, I don't understand the problem. You can use QM at the macroscopic level, but it is unnecessarily complex and has the same practical results as classical mechanics. Further, what do your friends mean with 'touch'. Why would it be relevant?

• [PDF] An introduction to macroscopic quantum phenomena and quantum ...

  In this book it is our intention to address the quantum mechanical effects that take place in properly chosen or built “macroscopic” systems. Start-ing from a very na¨ ıve point of view, we could always ask what happens to systems whose classical dynamics can be described by equations of motion equivalent to those of particles (or fields) in a given potential (or potential energy density). These can be represented by a generalized “coordinate” ϕpr, tq which could either describe a field variable [...] Amir O. Caldeira Campinas, June 2013 1 Introduction Since its very beginning, quantum mechanics has been developed for dealing with systems on the atomic or sub-atomic scale. For many decades, there has been no reason for thinking about its application to macroscopic systems. [...] Actually, macroscopic objects have even been used to show how bizarre quantum effects would appear if quantum mechanics were applied beyond its original realm. This is, for example, the essence of the so-called Schr¨ odinger cat paradox (Schr¨ odinger, 1935). However, due to recent advances in the design of systems on the meso- and nanoscopic scales, as well as on cryogenic techniques, this situation has changed drastically. It is now quite natural to ask whether a specific quantum effect,

• Nobel Prize in Physics 2025 - Popular information - NobelPrize.org

  This experiment has consequences for the understanding of quantum mechanics. Other types of quantum mechanical effects that are demonstrated on the macroscopic scale are composed of many tiny individual pieces and their separate quantum properties. The microscopic components are then combined to cause macroscopic phenomena such as lasers, superconductors and superfluid liquids. However, this experiment instead created a macroscopic effect – a measurable voltage – from a state that is in itself [...] Figure 3. Initially, the experiment has no voltage at all. It is as if there is a lever in the off position, and something is blocking from being moved to on. Without the effects of quantum mechanics, this state would remain unchanged. Suddenly, a voltage appears. This is as if the lever has moved from off to on, despite the barrier between the two. What happened in the experiment is called macroscopic quantum tunnelling.©Johan Jarnestad/The Royal Swedish Academy of Sciences [...] Theorists like Anthony Leggett have compared the laureates’ macroscopic quantum system with Erwin Schrödinger’s famous thought experiment featuring a cat in a box, where the cat would be both alive and dead if we did not look inside. (Erwin Schrödinger received the Nobel Prize in Physics 1933.) The intention of his thought experiment was to show the absurdity of this situation, because the special properties of quantum mechanics are often erased at a macroscopic scale. The quantum properties of