{"product_id":"twissa-hanbra-hanbury-brown-twiss-effect-physics-t-shirt","title":"Twissa \u0026 Hanbra – Hanbury Brown–Twiss Effect Physics T-Shirt","description":"\u003cp\u003eTwissa and Hanbra stand back to back at their searchlight dishes under Sirius. Their photons like to bunch.\u003c\/p\u003e\u003ch3\u003eThe Physics\u003c\/h3\u003e\u003cp\u003eCorrelating the intensity flickers at two separate detectors measures the coherence of light, and from it the angular size of a star. For thermal light the correlation at zero delay is 2 (bunching), for ideal laser light it is 1, and for single-photon sources it is below 1 (antibunching, a purely quantum effect).\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eg⁽²⁾(τ) = ⟨I(t) I(t+τ)⟩ \/ ⟨I⟩²\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eg⁽²⁾(τ): normalised intensity correlation (dimensionless)\u003c\/li\u003e\n\u003cli\u003eI: light intensity (W\/m²)\u003c\/li\u003e\n\u003cli\u003et: time (s)\u003c\/li\u003e\n\u003cli\u003eτ: delay between detectors (s)\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eR. Hanbury Brown and R. Q. Twiss measured Sirius with two searchlight mirrors (Nature, 1956): angular diameter 0.0068″ ± 0.0005″.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eHonest caveat:\u003c\/em\u003e The value 2 is the ideal for a single polarisation of thermal light; it is not what their 1956 electronics measured.\u003c\/p\u003e\u003ch3\u003eOn the shirt\u003c\/h3\u003e\u003cp\u003eFront: Twissa \u0026amp; Hanbra, the pixel-art character, with the title. Back: the g⁽²⁾ definition, thermal, laser and single-photon values, the Sirius result and the 1956 paper. Printed on a unisex tee.\u003c\/p\u003e","brand":"Printify","offers":[{"title":"S \/ White","offer_id":50936467587175,"sku":"81727818627281270109","price":29.99,"currency_code":"USD","in_stock":true},{"title":"S \/ Black","offer_id":50936467619943,"sku":"24113311575291247127","price":29.99,"currency_code":"USD","in_stock":true},{"title":"M \/ White","offer_id":50936467652711,"sku":"73684593406752473225","price":29.99,"currency_code":"USD","in_stock":true},{"title":"M \/ Black","offer_id":50936467685479,"sku":"14725626824861523754","price":29.99,"currency_code":"USD","in_stock":true},{"title":"L \/ White","offer_id":50936467718247,"sku":"31388222395734744483","price":29.99,"currency_code":"USD","in_stock":true},{"title":"L \/ Black","offer_id":50936467751015,"sku":"29372624704669159244","price":29.99,"currency_code":"USD","in_stock":true},{"title":"XL \/ White","offer_id":50936467783783,"sku":"51208128171716317891","price":29.99,"currency_code":"USD","in_stock":true},{"title":"XL \/ Black","offer_id":50936467816551,"sku":"15452900816236549288","price":29.99,"currency_code":"USD","in_stock":true},{"title":"2XL \/ White","offer_id":50936467849319,"sku":"32849789872585270079","price":29.99,"currency_code":"USD","in_stock":true},{"title":"2XL \/ Black","offer_id":50936467882087,"sku":"13225915047083129809","price":29.99,"currency_code":"USD","in_stock":true},{"title":"3XL \/ White","offer_id":50936467914855,"sku":"11331390305934484820","price":29.99,"currency_code":"USD","in_stock":true},{"title":"3XL \/ Black","offer_id":50936467947623,"sku":"31272634650166701825","price":29.99,"currency_code":"USD","in_stock":true},{"title":"4XL \/ White","offer_id":50936467980391,"sku":"29009732237355973989","price":29.99,"currency_code":"USD","in_stock":true},{"title":"4XL \/ Black","offer_id":50936468013159,"sku":"19884972188726646870","price":29.99,"currency_code":"USD","in_stock":true},{"title":"5XL \/ White","offer_id":50936468045927,"sku":"19540641715500592320","price":29.99,"currency_code":"USD","in_stock":true},{"title":"5XL \/ Black","offer_id":50936468078695,"sku":"16520317248283664150","price":29.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/8746\/9159\/files\/hanbury-brown-twiss_front_16_white.png?v=1793595268","url":"https:\/\/pixelatedphysics.com\/id\/products\/twissa-hanbra-hanbury-brown-twiss-effect-physics-t-shirt","provider":"Pixelated Physics","version":"1.0","type":"link"}