:Diffraction in time

{{short description|Diffraction of matter waves at the quantum scale}}

In quantum physics, diffraction in time is a phenomenon associated with the quantum dynamics of suddenly released matter waves initially confined in a region of space. It was introduced in 1952 by Ukrainian-Mexican physicist Marcos Moshinsky with the shutter problem.

{{Cite journal |last = Moshinsky |first=M.

|title=Diffraction in time

|journal=Physical Review

|volume=88

|issue=3

|pages=625–631

|year=1952

|doi = 10.1103/PhysRev.88.625

|bibcode = 1952PhRv...88..625M }}

A matter-wave beam stopped by an absorbing shutter exhibits an oscillatory density profile during its propagation after removal of the shutter. Whenever this propagation is accurately described by the time-dependent Schrödinger equation, the transient wave functions resemble the solutions that appear for the intensity of light subject to Fresnel diffraction by a straight edge. For this reason, the transient phenomenon was dubbed diffraction in time and has since then been recognised as ubiquitous in quantum dynamics.

{{Cite journal |last = Kleber |first=M.

|title=Exact solutions for time-dependent phenomena in quantum mechanics

|journal=Physics Reports

|volume=236

|issue=6

|pages=331–393

|year=1994

|doi = 10.1016/0370-1573(94)90029-9

|bibcode= 1994PhR...236..331K

}}

{{Cite journal |last1 = del Campo |first1=A.

|last2=García-Calderón|first2=G.

|last3=Muga|first3=J. G.

|title=Quantum transients

|journal=Physics Reports

|volume=476

|issue=1–3

|pages=1–50

|year=2009

|doi = 10.1016/j.physrep.2009.03.002

|arxiv = 0812.3034 |bibcode = 2009PhR...476....1D |s2cid=14760900

}}

The experimental confirmation of this phenomenon was only achieved about half a century later in the group of ultracold atoms directed by Jean Dalibard.

{{Cite journal

|last1 = Szriftgiser |first1=A.

|last2=Guéry-Odelin|first2=D.

|last3=Arndt|first3=M.

|last4=Dalibard|first4=J.

|title=Atomic Wave Diffraction and Interference Using Temporal Slits

|journal=Physical Review Letters

|volume=77

|issue=1

|pages=4–7

|year=1996

|doi =10.1103/PhysRevLett.77.4|bibcode=1996PhRvL..77....4S|pmid=10061757

}}