• Coalescia – Hong–Ou–Mandel physics T-shirt
  • Coalescia – Hong–Ou–Mandel physics T-shirt
  • Coalescia – Hong–Ou–Mandel physics T-shirt
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CoalesciaHong–Ou–Mandel Effect

Coalescia – Hong–Ou–Mandel Effect Physics T-Shirt

$29.99 USD
$29.99 USD
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Color
White · Black
Size
S–5XL
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What happens when two identical photons hit a beam splitter at the same moment? Coalescia and Coalesco always leave by the same exit. The two ways of getting one photon in each port cancel by interference, so the coincidence count drops to zero, the Hong–Ou–Mandel dip measured in 1987. Pixel-art unisex tee; equation, symbols and sources in the physics panel below.

Color
Size

Size guideS–5XL · inches

Details

Size & fitS–5XL

Unisex heavy cotton (Gildan 5000), classic fit.

SizeWidthLengthSleeve
S182815.1
M202916.5
L223018
XL243119.5
2XL263221
3XL283322.4
4XL303423.7
5XL323525

Measurements in inches, ±1.5 in tolerance.

ShippingFree US

Free US shipping · $10 flat shipping outside the US. Printed to order for you.

Delivery times & where we ship

Returns & replacements21 days

Every item is printed to order, so we can’t accept returns or exchanges for change of mind, or if you ordered the wrong size or colour.

Print defect, misprint, damage or the wrong item? We’ll send a free replacement, or a refund if you prefer. Report it within 21 days of delivery with a photo; no need to send it back.

Full refund & replacement policy

The physics

Two identical photons arrive at a 50:50 beam splitter at the same moment. Classically you would expect them to leave by different exits half the time. They never do.

There are two ways to get one photon in each output: both transmitted, or both reflected. For indistinguishable photons those two amplitudes cancel, so the photons always leave together. The coincidence count drops to zero: the Hong–Ou–Mandel dip, measured in 1987.

Make the photons slightly different, in timing or colour, and the overlap falls below one and the coincidences come back. Coalescia and Coalesco stay identical, so they always leave together.

Equations

\[|1,1\rangle \;\xrightarrow{\;50{:}50\;}\; \tfrac{1}{\sqrt{2}}\left(|2,0\rangle - |0,2\rangle\right)\]
\[P_{\text{coinc}} = \tfrac{1}{2}\left(1 - |\langle\psi_1|\psi_2\rangle|^{2}\right)\]
SymbolMeaningUnit
\(\) 1,1\rangle \(\mathrm{one photon in each input port}\)
\(\) 2,0\rangle, \(\mathrm{0,2\rangle}\)
\(P_{\text{coinc}}\) probability of one photon in each output (a coincidence) \(\mathrm{–}\)
\(\langle\psi_1\) \psi_2\rangle \(\mathrm{overlap of the two photons' states (1 = indistinguishable)}\)

Sources

  1. Hong, Ou & Mandel (1987) Measurement of subpicosecond time intervals between two photons by interference, Phys. Rev. Lett. 59, 2044
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