Editing Double-slit experiment (section)

====Hydrodynamic pilot wave analogs====

[[Hydrodynamic quantum analogs|Hydrodynamic analogs]] have been developed that can recreate various aspects of quantum mechanical systems, including single-particle interference through a double-slit.<ref name=Bush2015>{{cite journal|last1=Bush|first1=John WM|title=Pilot-wave hydrodynamics|journal=Annual Review of Fluid Mechanics|date=2015|volume=47|issue=1|pages=269–292|doi=10.1146/annurev-fluid-010814-014506|url=http://math.mit.edu/~bush/wordpress/wp-content/uploads/2015/01/Bush-AnnRev2015.pdf |archive-url=https://web.archive.org/web/20150621172430/http://math.mit.edu/~bush/wordpress/wp-content/uploads/2015/01/Bush-AnnRev2015.pdf |archive-date=2015-06-21 |url-status=live|access-date=21 June 2015|bibcode = 2015AnRFM..47..269B |hdl=1721.1/89790|hdl-access=free}}</ref> A silicone oil droplet, bouncing along the surface of a liquid, self-propels via resonant interactions with its own wave field. The droplet gently sloshes the liquid with every bounce. At the same time, ripples from past bounces affect its course. The droplet's interaction with its own ripples, which form what is known as a [[pilot wave]], causes it to exhibit behaviors previously thought to be peculiar to elementary particles – including behaviors customarily taken as evidence that elementary particles are spread through space like waves, without any specific location, until they are measured.<ref name=Bush2010>{{cite journal|last1=Bush|first1=John W. M.|title=Quantum mechanics writ large|journal=PNAS|volume=107|issue=41|pages=17455–17456|doi=10.1073/pnas.1012399107|bibcode = 2010PNAS..10717455B |pmc=2955131|year=2010|doi-access=free}}</ref><ref>{{Cite magazine |url=https://www.wired.com/2014/06/the-new-quantum-reality/ |title=Have We Been Interpreting Quantum Mechanics Wrong This Whole Time?|magazine=Wired |author=Natalie Wolchover |date=30 June 2014}}</ref>

Behaviors mimicked via this hydrodynamic pilot-wave system include quantum single particle diffraction,<ref name=CouderFort2012>{{cite journal|last1=Couder|first1=Y.|last2=Fort|first2=E.|title=Probabilities and trajectories in a classical wave–particle duality|journal=Journal of Physics: Conference Series|date=2012|volume=361|issue=1|page=012001|doi=10.1088/1742-6596/361/1/012001|bibcode = 2012JPhCS.361a2001C |doi-access=free}}</ref> tunneling, quantized orbits, orbital level splitting, spin, and multimodal statistics. It is also possible to infer uncertainty relations and exclusion principles.  Videos are available illustrating various features of this system. [[#External links|(See the External links.)]]

However, more complicated systems that involve two or more particles in superposition are not amenable to such a simple, classically intuitive explanation.<ref name="Baggott, Jim 2011 pp. 76">Baggott, Jim (2011). ''The Quantum Story: A History in 40 Moments''. New York: Oxford University Press. pp. 76.  ("The wavefunction of a system containing ''N'' particles depends on 3''N'' position coordinates and is a function in a 3''N''-dimensional configuration space or 'phase space'.  It is difficult to visualize a reality comprising imaginary functions in an abstract, multi-dimensional space.  No difficulty arises, however, if the imaginary functions are not to be given a real interpretation.")</ref> Accordingly, no hydrodynamic analog of entanglement has been developed.<ref name=Bush2015/> Nevertheless, optical analogs are possible.<ref>{{Cite journal | doi=10.1038/srep18574| pmid=26689679| pmc=4686973| title=Classical hypercorrelation and wave-optics analogy of quantum superdense coding| journal=Scientific Reports| volume=5| page=18574| year=2016| last1=Li| first1=Pengyun| last2=Sun| first2=Yifan| last3=Yang| first3=Zhenwei| last4=Song| first4=Xinbing| last5=Zhang| first5=Xiangdong| bibcode=2015NatSR...518574L}}</ref>