{"id":945,"date":"2026-10-15T01:00:00","date_gmt":"2026-10-14T16:00:00","guid":{"rendered":"https:\/\/quantumsea.net\/?p=945"},"modified":"2026-10-14T09:28:27","modified_gmt":"2026-10-14T00:28:27","slug":"qs-qutip-photon-g2-20261014","status":"publish","type":"post","link":"https:\/\/quantumsea.net\/?p=945","title":{"rendered":"\u5e73\u5747\u5149\u5b50\u6570\u3060\u3051\u3067\u306f\u5206\u304b\u3089\u306a\u3044\u5149\u306e\u63fa\u3089\u304e\u3000QuTiP\u306e\u4e8c\u6b21\u76f8\u95a2\u3067\u6bd4\u8f03\u3059\u308b"},"content":{"rendered":"<p>\u3042\u308b\u5149\u306e\u30e2\u30fc\u30c9\u306b\u542b\u307e\u308c\u308b\u5149\u5b50\u6570\u306e\u5e73\u5747\u304c2\u3060\u3063\u305f\u3068\u3057\u307e\u3059\u3002\u6bce\u56de\u5fc5\u305a2\u500b\u306a\u306e\u304b\u30011\u500b\u30843\u500b\u306a\u3069\u304c\u3070\u3089\u3064\u3044\u3066\u51fa\u308b\u306e\u304b\u3001\u3068\u304d\u306b\u306f\u591a\u304f\u3001\u3068\u304d\u306b\u306f\u307b\u3068\u3093\u3069\u51fa\u306a\u3044\u306e\u304b\u3002\u5e73\u5747\u3060\u3051\u3067\u306f\u3001\u3053\u306e\u9055\u3044\u306f\u898b\u3048\u307e\u305b\u3093\u3002<\/p>\n<p>\u5149\u5b50\u306e\u6570\u306e\u63fa\u3089\u304e\u3092\u6bd4\u8f03\u3059\u308b\u624b\u639b\u304b\u308a\u304c\u3001\u4e8c\u6b21\u76f8\u95a2g<sup>(2)<\/sup>\u3067\u3059\u3002\u3053\u3053\u3067\u306fQuTiP\u306e\u516c\u5f0f\u8cc7\u6599\u30685.1.1\u306e\u56fa\u5b9a\u5b9f\u88c5\u3092\u8aad\u307f\u3001\u6642\u9593\u5dee\u304c\u30bc\u30ed\u306eg<sup>(2)<\/sup>(0)\u3092\u4e2d\u5fc3\u306b\u3001\u540c\u3058\u5e73\u5747\u3092\u6301\u3064\u5149\u304c\u3069\u3046\u9055\u3046\u306e\u304b\u3092\u6574\u7406\u3057\u307e\u3059\u3002\u88c5\u7f6e\u306e\u5b9f\u6e2c\u3067\u306f\u306a\u304f\u3001\u5358\u4e00\u30e2\u30fc\u30c9\u3092\u4eee\u5b9a\u3057\u305f\u91cf\u5b50\u72b6\u614b\u3068\u72ec\u7acb\u8a08\u7b97\u306e\u6bd4\u8f03\u3067\u3059\u3002<sup class=\"source-note\"><a href=\"#ref-1\">[1]<\/a><a href=\"#ref-2\">[2]<\/a><\/sup><\/p>\n<section class=\"influvetor-quick-summary\" aria-label=\"\u7c21\u5358\u306b\u307e\u3068\u3081\u308b\u3068\uff1f\">\n<p><strong>\u7c21\u5358\u306b\u307e\u3068\u3081\u308b\u3068\uff1f<\/strong><\/p>\n<ul>\n<li>g<sup>(2)<\/sup>(0)\u306f\u5e73\u5747\u5149\u5b50\u6570\u3060\u3051\u3067\u306a\u304f\u3001\u7570\u306a\u308b2\u500b\u306e\u5149\u5b50\u304b\u3089\u306a\u308b\u7d44\u306e\u5e73\u5747\u3092\u898b\u307e\u3059\u3002\u540c\u3058\u5e73\u5747\u3067\u3082\u3001\u5149\u5b50\u6570\u306e\u63fa\u3089\u304e\u65b9\u306b\u3088\u3063\u3066\u5024\u304c\u5909\u308f\u308a\u307e\u3059\u3002<\/li>\n<li>\u5e73\u57472\u306e\u7406\u60f3\u4f8b\u3067\u306f\u30012\u5149\u5b50\u306eFock\u72b6\u614b\u304c0.5\u3001\u30b3\u30d2\u30fc\u30ec\u30f3\u30c8\u72b6\u614b\u304c1\u3001\u5358\u4e00\u30e2\u30fc\u30c9\u306e\u71b1\u72b6\u614b\u304c2\u3067\u3059\u3002\u305f\u3060\u3057\u3001\u3053\u306e\u4e00\u3064\u306e\u5024\u3060\u3051\u3067\u72b6\u614b\u5168\u4f53\u306f\u6c7a\u307e\u308a\u307e\u305b\u3093\u3002<\/li>\n<li>\u30bc\u30ed\u3067\u306a\u3044\u5e73\u5747\u3001\u5bfe\u8c61\u30e2\u30fc\u30c9\u3001\u6642\u523b\u3001\u898f\u683c\u5316\u306e\u5206\u6bcd\u3092\u305d\u308d\u3048\u307e\u3059\u3002\u6642\u9593\u5dee\u3092\u3064\u3051\u305f\u76f8\u95a2\u3067\u306f\u3001\u5b9a\u5e38\u306a\u5834\u5408\u3068\u5e73\u5747\u304c\u5909\u5316\u3059\u308b\u5834\u5408\u3092\u533a\u5225\u3057\u307e\u3059\u3002<\/li>\n<\/ul>\n<\/section>\n<h2>\u5e73\u5747\u306e\u6b21\u306b\u3001\u5149\u5b50\u306e\u300c\u7d44\u300d\u3092\u6570\u3048\u308b<\/h2>\n<p>\u5149\u306e\u30e2\u30fc\u30c9\u3068\u306f\u3001\u7a7a\u9593\u7684\u306a\u5f62\u3084\u5468\u6ce2\u6570\u306a\u3069\u3067\u533a\u5225\u3059\u308b\u5834\u306e\u4e00\u3064\u306e\u81ea\u7531\u5ea6\u3067\u3059\u3002\u3053\u3053\u3067\u306f\u4e00\u3064\u306e\u30e2\u30fc\u30c9\u3060\u3051\u3092\u6271\u3044\u3001\u540c\u3058\u91cf\u5b50\u72b6\u614b\u3092\u7528\u610f\u3057\u3066\u5149\u5b50\u6570\u3092\u6e2c\u308b\u3068\u304d\u306e\u5206\u5e03\u3092\u8003\u3048\u307e\u3059\u3002\u5149\u5b50\u6570\u6f14\u7b97\u5b50\u3092n\uff1da<sup>\u2020<\/sup>a\u3068\u66f8\u304d\u3001a\u306f\u5149\u5b50\u3092\u4e00\u3064\u6e1b\u3089\u3059\u6d88\u6ec5\u6f14\u7b97\u5b50\u3001a<sup>\u2020<\/sup>\u306f\u5897\u3084\u3059\u751f\u6210\u6f14\u7b97\u5b50\u3067\u3059\u3002\u5c71\u62ec\u5f27\u3008 \u3009\u306f\u3001\u305d\u306e\u72b6\u614b\u3067\u306e\u5e73\u5747\u3092\u8868\u3057\u307e\u3059\u3002<\/p>\n<p>\u6642\u9593\u5dee\u30bc\u30ed\u306e\u4e8c\u6b21\u76f8\u95a2\u306f\u3001\u5e73\u5747\u5149\u5b50\u6570\u3008n\u3009\u304c\u30bc\u30ed\u3067\u306a\u3044\u3068\u304d\u3001\u6b21\u306e\u5f62\u306b\u306a\u308a\u307e\u3059\u3002<sup class=\"source-note\"><a href=\"#ref-1\">[1]<\/a><a href=\"#ref-2\">[2]<\/a><\/sup><\/p>\n<p style=\"overflow-x:auto;\">g<sup>(2)<\/sup>(0)\uff1d\u3008a<sup>\u2020<\/sup>a<sup>\u2020<\/sup>aa\u3009 \/ \u3008a<sup>\u2020<\/sup>a\u3009<sup>2<\/sup>\uff1d\u3008n(n\u22121)\u3009 \/ \u3008n\u3009<sup>2<\/sup><\/p>\n<p>\u5206\u5b50\u304c\u3008n<sup>2<\/sup>\u3009\u3067\u306f\u306a\u3044\u70b9\u304c\u5927\u5207\u3067\u3059\u3002n\u500b\u306e\u4e2d\u304b\u3089\u6700\u521d\u306e\u5149\u5b50\u3092\u4e00\u3064\u9078\u3076\u65b9\u6cd5\u306fn\u901a\u308a\u3001\u540c\u3058\u5149\u5b50\u3092\u9664\u3044\u3066\u6b21\u3092\u9078\u3076\u65b9\u6cd5\u306fn\u22121\u901a\u308a\u306a\u306e\u3067\u3001\u9806\u5e8f\u3092\u533a\u5225\u3057\u305f\u7d44\u306fn(n\u22121)\u901a\u308a\u3067\u3059\u3002\u3053\u308c\u306f2\u500b\u306e\u7d44\u306b\u95a2\u308f\u308b\u91cf\u3067\u3042\u308a\u3001\u5149\u5b50\u3092\u81ea\u5206\u81ea\u8eab\u3068\u7d44\u306b\u3059\u308b\u5206\u306f\u6570\u3048\u3066\u3044\u307e\u305b\u3093\u3002\u91cf\u5b50\u6f14\u7b97\u5b50\u3067\u3082\u3001aa\u304c|n\u27e9\u3078\u4f5c\u7528\u3059\u308b\u4fc2\u6570\u306e\u4e8c\u4e57\u304cn(n\u22121)\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<p>\u305f\u3068\u3048\u3070\u6bce\u56de2\u500b\u306a\u3089\u3001\u7d44\u306e\u6570\u306f\u5e38\u306b2\u3067\u3059\u3002\u4e00\u65b9\u3001\u5e73\u5747\u304c2\u306b\u306a\u308b\u3088\u3046\u306b\u5149\u5b50\u6570\u304c\u3070\u3089\u3064\u304f\u3068\u3001\u591a\u304f\u51fa\u308b\u56de\u306e\u7d44\u306e\u6570\u306f\u4e8c\u4e57\u306b\u8fd1\u3044\u901f\u3055\u3067\u5897\u3048\u307e\u3059\u3002\u5e73\u5747\u5149\u5b50\u6570\u3092\u305d\u308d\u3048\u3066\u3082\u3001\u5206\u5b50\u306b\u306f\u305d\u306e\u9055\u3044\u304c\u6b8b\u308a\u307e\u3059\u3002g<sup>(2)<\/sup>(0)\u306f\u5149\u5b50\u6570\u305d\u306e\u3082\u306e\u3067\u306f\u306a\u304f\u3001\u3053\u306e\u5e73\u5747\u3067\u898f\u683c\u5316\u3057\u305f\u7121\u6b21\u5143\u306e\u6307\u6a19\u3067\u3059\u3002<\/p>\n<h2>\u5e73\u57472\u306e\u4e09\u3064\u306e\u72b6\u614b\u3092\u6bd4\u3079\u308b<\/h2>\n<p>\u9055\u3044\u3092\u5177\u4f53\u7684\u306b\u3059\u308b\u305f\u3081\u3001\u7406\u60f3\u7684\u306a\u4e09\u3064\u306e\u72b6\u614b\u3092\u6bd4\u3079\u307e\u3059\u3002Fock\u72b6\u614b|2\u27e9\u306f\u3001\u5149\u5b50\u6570\u304c\u5fc5\u305a2\u3068\u306a\u308b\u72b6\u614b\u3067\u3059\u3002\u30b3\u30d2\u30fc\u30ec\u30f3\u30c8\u72b6\u614b\u3067\u306f\u5149\u5b50\u6570\u304c\u30dd\u30a2\u30bd\u30f3\u5206\u5e03\u306b\u5f93\u3044\u3001\u5e73\u57472\u306e\u5834\u5408\u306e\u5206\u6563\u30822\u306b\u306a\u308a\u307e\u3059\u3002\u5358\u4e00\u30e2\u30fc\u30c9\u306e\u71b1\u72b6\u614b\u3067\u306f\u5e7e\u4f55\u5206\u5e03\u3068\u306a\u308a\u3001\u540c\u3058\u5e73\u57472\u3067\u3082\u5206\u6563\u306f6\u3067\u3059\u3002\u5206\u6563\u306f\u3001\u5e73\u5747\u304b\u3089\u306e\u305a\u308c\u3092\u4e8c\u4e57\u3057\u3066\u5e73\u5747\u3057\u305f\u3001\u3070\u3089\u3064\u304d\u306e\u5927\u304d\u3055\u3067\u3059\u3002<sup class=\"source-note\"><a href=\"#ref-3\">[3]<\/a><\/sup><\/p>\n<p>\u5149\u5b50\u6570\u304cn\u3068\u306a\u308b\u78ba\u7387\u3092P(n)\u3068\u3059\u308b\u3068\u3001\u4eca\u56de\u306e\u30b3\u30d2\u30fc\u30ec\u30f3\u30c8\u72b6\u614b\u306fP(n)\uff1de<sup>\u22122<\/sup>2<sup>n<\/sup>\/n!\u3001\u71b1\u72b6\u614b\u306fP(n)\uff1d(1\/3)(2\/3)<sup>n<\/sup>\u3067\u3059\u3002\u3053\u308c\u3089\u306e\u5206\u5e03\u304b\u3089\u5e73\u5747\u3068\u7d44\u306e\u6570\u3092\u8a08\u7b97\u3059\u308b\u3068\u3001\u6b21\u306e\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n<div style=\"max-width:100%;overflow-x:auto;\" tabindex=\"0\" aria-label=\"\u5e73\u5747\u5149\u5b50\u65702\u306e\u7406\u60f3\u72b6\u614b\u306e\u6bd4\u8f03\u3002\u6a2a\u306b\u30b9\u30af\u30ed\u30fc\u30eb\u3067\u304d\u307e\u3059\u3002\">\n<table style=\"width:100%;min-width:640px;border-collapse:collapse;\">\n<caption>\u5358\u4e00\u30e2\u30fc\u30c9\u30fb\u5e73\u5747\u5149\u5b50\u65702\u306e\u72ec\u81ea\u8a08\u7b97\u3002\u7121\u9650\u306e\u5149\u5b50\u6570\u7a7a\u9593\u306b\u304a\u3051\u308b\u7406\u8ad6\u5024\u3067\u3001\u5b9f\u9a13\u5024\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/caption>\n<thead>\n<tr>\n<th scope=\"col\">\u72b6\u614b<\/th>\n<th scope=\"col\">\u3008n\u3009<\/th>\n<th scope=\"col\">\u5206\u6563<\/th>\n<th scope=\"col\">\u3008n(n\u22121)\u3009<\/th>\n<th scope=\"col\">g<sup>(2)<\/sup>(0)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<th scope=\"row\">Fock\u72b6\u614b |2\u27e9<\/th>\n<td>2<\/td>\n<td>0<\/td>\n<td>2<\/td>\n<td>0.5<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">\u30b3\u30d2\u30fc\u30ec\u30f3\u30c8\u72b6\u614b<br \/>|\u03b1|<sup>2<\/sup>\uff1d2<\/th>\n<td>2<\/td>\n<td>2<\/td>\n<td>4<\/td>\n<td>1<\/td>\n<\/tr>\n<tr>\n<th scope=\"row\">\u5358\u4e00\u30e2\u30fc\u30c9\u306e\u71b1\u72b6\u614b<\/th>\n<td>2<\/td>\n<td>6<\/td>\n<td>8<\/td>\n<td>2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>\u8868\u306f\u78ba\u7387\u5206\u5e03\u306e\u5f0f\u304b\u3089\u5c0e\u304d\u3001\u5149\u5b50\u6570\u57fa\u5e95\u306e\u6d88\u6ec5\u6f14\u7b97\u5b50\u3092\u5225\u306b\u7d44\u307f\u7acb\u3066\u305f\u884c\u5217\u8a08\u7b97\u3067\u3082\u7167\u5408\u3057\u307e\u3057\u305f\u3002\u6b8b\u3059\u57fa\u5e95\u309210\u300120\u300140\u300180\u72b6\u614b\u3078\u5897\u3084\u3057\u3066\u78ba\u8a8d\u3057\u300180\u72b6\u614b\u3067\u306eg<sup>(2)<\/sup>(0)\u306e\u7406\u8ad6\u5024\u3068\u306e\u5dee\u306f\u3001\u4e09\u4f8b\u3068\u30821.3\u00d710<sup>\u221211<\/sup>\u4ee5\u4e0b\u3067\u3057\u305f\u3002QuTiP\u672c\u4f53\u3084\u5149\u6e90\u3092\u52d5\u304b\u3057\u305f\u7d50\u679c\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<p>\u71b1\u72b6\u614b\u306f\u5149\u5b50\u6570\u306e\u5927\u304d\u3044\u5074\u306b\u3082\u78ba\u7387\u304c\u6b8b\u308b\u305f\u3081\u3001\u5e73\u5747\u3060\u3051\u3067\u306a\u304f\u4e8c\u6b21\u306e\u91cf\u3082\u53ce\u675f\u3057\u3066\u3044\u308b\u304b\u3092\u898b\u307e\u3059\u3002\u4eca\u56de\u306e\u6570\u5024\u7167\u5408\u3067\u306f\u3001\u89e3\u6790\u5f0f\u306e\u4fc2\u6570\u3092\u6709\u9650\u7bc4\u56f2\u3078\u5207\u308a\u51fa\u3057\u3066\u6b63\u898f\u5316\u3057\u307e\u3057\u305f\u3002QuTiP\u306e<code>coherent<\/code>\u306b\u306f\u6709\u9650\u7a7a\u9593\u306e\u5909\u4f4d\u6f14\u7b97\u5b50\u3092\u4f7f\u3046\u65b9\u6cd5\u3082\u3042\u308b\u305f\u3081\u3001\u540c\u3058N\u3068\u3044\u3046\u8868\u793a\u3060\u3051\u3067\u69cb\u6210\u6cd5\u307e\u3067\u540c\u4e00\u3068\u306f\u3057\u307e\u305b\u3093\u3002<sup class=\"source-note\"><a href=\"#ref-3\">[3]<\/a><\/sup><\/p>\n<h2>g<sup>(2)<\/sup>(0)\u304c1\u3088\u308a\u5c0f\u3055\u3044\u3001\u307e\u305f\u306f\u5927\u304d\u3044\u3068\u4f55\u304c\u5206\u304b\u308b\u304b<\/h2>\n<p>\u5206\u6563Var(n)\uff1d\u3008n<sup>2<\/sup>\u3009\u2212\u3008n\u3009<sup>2<\/sup>\u3092\u4f7f\u3046\u3068\u3001\u540c\u3058\u5f0f\u3092\u6b21\u306e\u3088\u3046\u306b\u66f8\u304d\u76f4\u305b\u307e\u3059\u3002<\/p>\n<p style=\"overflow-x:auto;\">g<sup>(2)<\/sup>(0)\uff1d1\uff0b[Var(n)\u2212\u3008n\u3009] \/ \u3008n\u3009<sup>2<\/sup><\/p>\n<p>\u3057\u305f\u304c\u3063\u3066\u3001\u3053\u306e\u5358\u4e00\u30e2\u30fc\u30c9\u306e\u6761\u4ef6\u3067g<sup>(2)<\/sup>(0)\u304c1\u3088\u308a\u5c0f\u3055\u3051\u308c\u3070\u3001\u5206\u6563\u306f\u30dd\u30a2\u30bd\u30f3\u5206\u5e03\u306e\u57fa\u6e96\u3067\u3042\u308b\u5e73\u5747\u5149\u5b50\u6570\u3088\u308a\u5c0f\u3055\u304f\u306a\u308a\u307e\u3059\u30021\u3088\u308a\u5927\u304d\u3051\u308c\u3070\u3001\u305d\u306e\u57fa\u6e96\u3088\u308a\u5927\u304d\u3044\u63fa\u3089\u304e\u3067\u3059\u3002\u5149\u5b50\u304c\u307e\u3068\u307e\u3063\u3066\u73fe\u308c\u308b\u50be\u5411\u3092\u8ad6\u3058\u308b\u969b\u306e\u624b\u639b\u304b\u308a\u306b\u306a\u308a\u307e\u3059\u304c\u3001\u6642\u9593\u3092\u305a\u3089\u3057\u305f\u3068\u304d\u306e\u76f8\u95a2\u306e\u5f62\u306f\u3001\u3053\u308c\u3060\u3051\u3067\u306f\u5206\u304b\u308a\u307e\u305b\u3093\u3002<\/p>\n<p><strong>1\u672a\u6e80\u3068\u3044\u3046\u3060\u3051\u3067\u300c\u5fc5\u305a1\u500b\u305a\u3064\u51fa\u308b\u300d\u3068\u306f\u8a00\u3048\u307e\u305b\u3093\u3002<\/strong>\u8868\u306eFock\u72b6\u614b|2\u27e9\u306fg<sup>(2)<\/sup>(0)\uff1d0.5\u3067\u3059\u304c\u3001\u6e2c\u308c\u3070\u5fc5\u305a2\u500b\u3067\u3059\u3002\u4e00\u822c\u306b\u3001\u5149\u5b50\u6570m\u304c\u6b63\u306e\u6574\u6570\u3067\u56fa\u5b9a\u3055\u308c\u305fFock\u72b6\u614b\u3067\u306fg<sup>(2)<\/sup>(0)\uff1d1\u22121\/m\u3068\u306a\u308a\u307e\u3059\u3002\u5358\u4e00\u5149\u5b50\u306e\u7406\u60f3\u72b6\u614b|1\u27e9\u306a\u30890\u3067\u3059\u304c\u30010.5\u3092\u898b\u3066\u305d\u308c\u3068\u540c\u3058\u3060\u3068\u6271\u3046\u3053\u3068\u306f\u3067\u304d\u307e\u305b\u3093\u3002<\/p>\n<p>\u9006\u306b\u3001g<sup>(2)<\/sup>(0)\uff1d1\u3060\u304b\u3089\u72b6\u614b\u304c\u7d14\u7c8b\u306a\u30b3\u30d2\u30fc\u30ec\u30f3\u30c8\u72b6\u614b\u3060\u3068\u3082\u65ad\u5b9a\u3067\u304d\u307e\u305b\u3093\u3002\u5149\u5b50\u6570\u5206\u5e03\u304c\u540c\u3058\u30dd\u30a2\u30bd\u30f3\u5206\u5e03\u3067\u3082\u3001\u7570\u306a\u308b\u5149\u5b50\u6570\u6210\u5206\u306e\u4f4d\u76f8\u306e\u95a2\u4fc2\u3092\u5e73\u5747\u3057\u3066\u5931\u308f\u305b\u305f\u6df7\u5408\u72b6\u614b\u3092\u4f5c\u308c\u307e\u3059\u3002\u5149\u5b50\u6570\u306e\u5e73\u5747\u3068\u4e8c\u6b21\u76f8\u95a2\u306f\u540c\u3058\u3067\u3082\u3001\u5bc6\u5ea6\u884c\u5217\u306e\u975e\u5bfe\u89d2\u6210\u5206\u306f\u9055\u3044\u307e\u3059\u3002\u4eca\u56de\u306e\u72ec\u7acb\u8a08\u7b97\u3067\u3082\u3001\u5e73\u5747\u3068\u4e8c\u6b21\u76f8\u95a2\u304c\u540c\u3058\u3067\u3082\u5bc6\u5ea6\u884c\u5217\u306f\u7570\u306a\u308b\u3053\u3068\u3092\u78ba\u8a8d\u3057\u307e\u3057\u305f\u3002g<sup>(2)<\/sup>(0)\u306f\u6709\u7528\u306a\u6bd4\u8f03\u8ef8\u3067\u3059\u304c\u3001\u72b6\u614b\u5168\u4f53\u3092\u5fa9\u5143\u3059\u308b\u60c5\u5831\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<h2>\u6642\u9593\u5dee\u3092\u3064\u3051\u308b\u306a\u3089\u3001\u5206\u6bcd\u3082\u6642\u523b\u306b\u5408\u308f\u305b\u308b<\/h2>\n<p>\u30bc\u30ed\u9045\u5ef6\u306e\u6bd4\u8f03\u306f\u3001\u3042\u308b\u6642\u70b9\u306e\u72b6\u614b\u306e\u5149\u5b50\u6570\u5206\u5e03\u304b\u3089\u884c\u3048\u307e\u3059\u3002\u3053\u3053\u307e\u3067\u306e\u8868\u306b\u3001\u6642\u9593\u306b\u4f9d\u5b58\u3057\u306a\u3044\u5b9a\u5e38\u72b6\u614b\u3068\u3044\u3046\u4eee\u5b9a\u306f\u5fc5\u8981\u3042\u308a\u307e\u305b\u3093\u3002\u4e00\u65b9\u3001\u6642\u9593\u5dee\u03c4\u3092\u3064\u3051\u3066g<sup>(2)<\/sup>(\u03c4)\u3092\u6c42\u3081\u308b\u3068\u304d\u306f\u3001\u305d\u306e\u9593\u306b\u72b6\u614b\u304c\u3069\u3046\u5909\u308f\u308b\u304b\u3068\u3044\u3046\u30e2\u30c7\u30eb\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n<p>QuTiP 5.1.1\u306e\u56fa\u5b9a\u5b9f\u88c5<code style=\"overflow-wrap:anywhere;\">coherence_function_g2<\/code>\u306f\u3001\u521d\u671f\u6642\u523b\u30920\u3068\u3057\u3066\u3001\u975e\u898f\u683c\u5316\u306eG<sup>(2)<\/sup>(\u03c4)\u3068\u3001\u898f\u683c\u5316\u3057\u305fg<sup>(2)<\/sup>(\u03c4)\u306e\u4e21\u65b9\u3092\u8fd4\u3057\u307e\u3059\u3002\u521d\u671f\u72b6\u614b\u3092\u6307\u5b9a\u3059\u308b\u7d4c\u8def\u3067\u306f\u3001\u5e73\u5747\u5149\u5b50\u6570\u3092\u6642\u9593\u306b\u6cbf\u3063\u3066\u6c42\u3081\u3001\u5206\u6bcd\u306bn\u0304(0)n\u0304(\u03c4)\u3092\u4f7f\u3044\u307e\u3059\u3002\u3053\u3053\u3067n\u0304\u306f\u5e73\u5747\u5149\u5b50\u6570\u3067\u3059\u3002<sup class=\"source-note\"><a href=\"#ref-2\">[2]<\/a><\/sup><\/p>\n<p style=\"overflow-x:auto;\">g<sup>(2)<\/sup>(\u03c4)\uff1d\u3008a<sup>\u2020<\/sup>(0)a<sup>\u2020<\/sup>(\u03c4)a(\u03c4)a(0)\u3009 \/ [n\u0304(0)n\u0304(\u03c4)]<\/p>\n<p>\u5b9a\u5e38\u306a\u72b6\u614b\u3067\u5e73\u5747\u304c\u4e00\u5b9a\u306a\u3089\u3001\u3053\u306e\u5206\u6bcd\u306fn\u0304<sup>2<\/sup>\u306b\u306a\u308a\u307e\u3059\u3002\u6e1b\u8870\u4e2d\u306a\u3069\u3067\u5e73\u5747\u304c\u5909\u308f\u308b\u5834\u5408\u306b\u3001\u521d\u671f\u5e73\u5747\u306e\u4e8c\u4e57\u3067\u5272\u308a\u7d9a\u3051\u308b\u3068\u3001\u5225\u306e\u91cf\u3092\u6bd4\u8f03\u3059\u308b\u3053\u3068\u306b\u306a\u308a\u307e\u3059\u3002\u516c\u5f0f\u30ac\u30a4\u30c9\u306e\u8aac\u660e\u5f0f\u3068\u3001\u521d\u671f\u72b6\u614b\u3092\u6642\u9593\u767a\u5c55\u3055\u305b\u308b\u4f8b\u306e\u5206\u6bcd\u3092\u8aad\u3080\u3068\u304d\u3082\u3001\u3053\u306e\u6761\u4ef6\u3092\u5206\u3051\u308b\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\u3002<sup class=\"source-note\"><a href=\"#ref-1\">[1]<\/a><a href=\"#ref-2\">[2]<\/a><\/sup><\/p>\n<p>\u540c\u95a2\u6570\u3067<code>state0=None<\/code>\u3092\u6307\u5b9a\u3059\u308b\u3068\u5b9a\u5e38\u72b6\u614b\u3092\u6c42\u3081\u3066\u4f7f\u3044\u307e\u3059\u304c\u3001\u6587\u66f8\u306b\u8a18\u8f09\u3055\u308c\u305f\u6761\u4ef6\u306f\u3001\u6642\u9593\u306b\u4f9d\u5b58\u3057\u306a\u3044\u30cf\u30df\u30eb\u30c8\u30cb\u30a2\u30f3\u3068\u5d29\u58ca\u6f14\u7b97\u5b50\u304c\u3042\u308b\u3053\u3068\u3067\u3059\u3002\u9045\u5ef6\u76f8\u95a2\u306e\u8a08\u7b97\u306b\u306f\u91cf\u5b50\u56de\u5e30\u5b9a\u7406\u3092\u7528\u3044\u308b\u305f\u3081\u3001\u6642\u9593\u767a\u5c55\u306e\u30e2\u30c7\u30eb\u3068\u305d\u306e\u9069\u7528\u6761\u4ef6\u3092\u5f15\u304d\u7d99\u304e\u307e\u3059\u3002\u4efb\u610f\u306e\u8a18\u61b6\u52b9\u679c\u3092\u6301\u3064\u74b0\u5883\u3067\u3001\u540c\u3058\u624b\u7d9a\u304d\u3092\u4f7f\u3048\u3070\u3088\u3044\u3068\u3044\u3046\u610f\u5473\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<p>\u516c\u5f0f\u4f8b\u306e\u4e09\u3064\u306e\u66f2\u7dda\u306f\u3001\u6307\u5b9a\u3057\u305f\u71b1\u6d74\u3068\u306e\u76f8\u4e92\u4f5c\u7528\u306e\u4e0b\u3067\u306e\u6642\u9593\u5909\u5316\u3067\u3059\u3002g<sup>(2)<\/sup>(0)\u304c0.5\u30011\u30012\u3067\u3042\u308b\u3053\u3068\u304b\u3089\u3001\u3069\u306e\u5149\u6e90\u3067\u3082\u540c\u3058\u6642\u9593\u5c3a\u5ea6\u3067\u540c\u3058\u66f2\u7dda\u3078\u9032\u3080\u3068\u306f\u8a00\u3048\u307e\u305b\u3093\u3002\u672c\u7a3f\u306e\u8868\u306f\u30bc\u30ed\u9045\u5ef6\u306e\u6570\u5024\u3067\u3042\u308a\u3001\u9045\u5ef6\u66f2\u7dda\u3092\u72ec\u7acb\u306b\u518d\u8a08\u7b97\u3057\u305f\u3082\u306e\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<h2>\u6bd4\u8f03\u306e\u524d\u306b\u3001\u5e73\u5747\u30fb\u30e2\u30fc\u30c9\u30fb\u8a08\u7b97\u6761\u4ef6\u3092\u305d\u308d\u3048\u308b<\/h2>\n<p>\u307e\u305a\u3001\u6bd4\u8f03\u3059\u308b\u5bfe\u8c61\u304c\u540c\u3058\u30e2\u30fc\u30c9\u306a\u306e\u304b\u3001\u8907\u6570\u306e\u5468\u6ce2\u6570\u3084\u7a7a\u9593\u30e2\u30fc\u30c9\u3092\u307e\u3068\u3081\u305f\u3082\u306e\u306a\u306e\u304b\u3092\u78ba\u8a8d\u3057\u307e\u3059\u3002\u8868\u306e\u71b1\u72b6\u614b\u306e\u50242\u306f\u5358\u4e00\u30e2\u30fc\u30c9\u306e\u7406\u60f3\u4f8b\u3067\u3042\u308a\u3001\u8907\u6570\u30e2\u30fc\u30c9\u3092\u307e\u3068\u3081\u305f\u6e2c\u5b9a\u3078\u305d\u306e\u307e\u307e\u5f53\u3066\u306f\u3081\u308b\u6570\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/p>\n<p>\u6b21\u306b\u3001\u5e73\u5747\u5149\u5b50\u6570\u304c\u30bc\u30ed\u3067\u306a\u3044\u304b\u3092\u78ba\u8a8d\u3057\u307e\u3059\u3002\u771f\u7a7a\u3067\u306f\u5206\u5b50\u3082\u5206\u6bcd\u3082\u30bc\u30ed\u3067\u3001\u898f\u683c\u5316\u3057\u305fg<sup>(2)<\/sup>(0)\u306f\u5b9a\u7fa9\u3067\u304d\u307e\u305b\u3093\u3002\u5e73\u5747\u304c\u975e\u5e38\u306b\u5c0f\u3055\u3044\u8a08\u7b97\u3067\u3082\u3001\u6bd4\u3060\u3051\u3092\u898b\u308b\u524d\u306b\u3001\u5206\u5b50G<sup>(2)<\/sup>\u3068\u5e73\u5747\u306e\u5024\u3001\u6570\u5024\u7cbe\u5ea6\u3092\u78ba\u8a8d\u3057\u305f\u3044\u3068\u3053\u308d\u3067\u3059\u3002QuTiP\u304c\u4e21\u65b9\u306e\u76f8\u95a2\u5024\u3092\u8fd4\u3059\u3053\u3068\u306f\u3001\u3053\u306e\u5207\u308a\u5206\u3051\u306b\u5f79\u7acb\u3061\u307e\u3059\u3002<\/p>\n<p>\u5b9f\u9a13\u3068\u6bd4\u8f03\u3059\u308b\u306a\u3089\u3001\u691c\u51fa\u3059\u308b\u6642\u9593\u5e45\u3084\u5468\u6ce2\u6570\u5e2f\u3001\u80cc\u666f\u5149\u3001\u691c\u51fa\u5668\u306e\u5fdc\u7b54\u306a\u3069\u3092\u542b\u3080\u6e2c\u5b9a\u6761\u4ef6\u3068\u3001\u30e2\u30c7\u30eb\u304c\u8868\u3059\u91cf\u3092\u5bfe\u5fdc\u3055\u305b\u307e\u3059\u3002\u7406\u60f3\u72b6\u614b\u306e\u5206\u6563\u304c\u5927\u304d\u3044\u3053\u3068\u3068\u3001\u6709\u9650\u56de\u306e\u6e2c\u5b9a\u304b\u3089g<sup>(2)<\/sup>\u3092\u63a8\u5b9a\u3057\u305f\u5024\u306e\u8aa4\u5dee\u304c\u5927\u304d\u3044\u3053\u3068\u3082\u5225\u3067\u3059\u3002\u5f8c\u8005\u306b\u306f\u6a19\u672c\u6570\u3068\u63a8\u5b9a\u624b\u9806\u306e\u60c5\u5831\u304c\u5fc5\u8981\u3067\u3059\u3002<\/p>\n<p>\u5e73\u5747\u5149\u5b50\u6570\u306b\u52a0\u3048\u3066\u300c\u7d44\u306e\u5e73\u5747\u300d\u3092\u9078\u3076\u3068\u3001\u898b\u3048\u3066\u3044\u306a\u304b\u3063\u305f\u63fa\u3089\u304e\u304c\u6bd4\u8f03\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002\u305d\u306e\u3046\u3048\u3067\u3001\u6570\u304c\u56fa\u5b9a\u3055\u308c\u3066\u3044\u308b\u306e\u304b\u3001\u4f4d\u76f8\u306e\u95a2\u4fc2\u307e\u3067\u77e5\u308a\u305f\u3044\u306e\u304b\u3001\u6642\u9593\u3092\u307e\u305f\u3050\u5909\u5316\u3092\u77e5\u308a\u305f\u3044\u306e\u304b\u3092\u5206\u3051\u308b\u3002g<sup>(2)<\/sup>\u304c\u7b54\u3048\u308b\u554f\u3044\u3068\u3001\u8ffd\u52a0\u306e\u89b3\u6e2c\u91cf\u304c\u5fc5\u8981\u306a\u554f\u3044\u3092\u5207\u308a\u5206\u3051\u308b\u3053\u3068\u304c\u3001\u8a08\u7b97\u3084\u6e2c\u5b9a\u306e\u4f7f\u3044\u9053\u306b\u3064\u306a\u304c\u308a\u307e\u3059\u3002<\/p>\n<h2>\u53c2\u8003\u8cc7\u6599<\/h2>\n<ol>\n<li id=\"ref-1\">QuTiP 5.1 Documentation, <a href=\"https:\/\/qutip.readthedocs.io\/en\/qutip-5.1.x\/guide\/guide-correlation.html\">Two-time correlation functions<\/a>\u3002\u4e8c\u6642\u523b\u76f8\u95a2\u3001\u5b9a\u5e38\u6027\u3001\u4e8c\u6b21\u76f8\u95a2\u306e\u5b9a\u7fa9\u3068\u71b1\u6d74\u4e0b\u306e\u8a08\u7b97\u4f8b\u3002<\/li>\n<li id=\"ref-2\">QuTiP 5.1.1, <a href=\"https:\/\/github.com\/qutip\/qutip\/blob\/7accc77a70a08f965a29fdd13515f79cdcab9703\/qutip\/solver\/correlation.py\">correlation.py\u306e\u56fa\u5b9a\u5b9f\u88c5<\/a>\u3002coherence_function_g2\u306e\u5165\u529b\u6761\u4ef6\u3001\u5e73\u5747\u306e\u8a08\u7b97\u3001G2\u3068g2\u306e\u898f\u683c\u5316\u3002\u6700\u65b0\u7248\u3092\u793a\u3059\u3082\u306e\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002<\/li>\n<li id=\"ref-3\">QuTiP 5.1.1, <a href=\"https:\/\/github.com\/qutip\/qutip\/blob\/7accc77a70a08f965a29fdd13515f79cdcab9703\/qutip\/core\/states.py\">states.py\u306e\u56fa\u5b9a\u5b9f\u88c5<\/a>\u3002coherent\u30fbfock_dm\u30fbthermal_dm\u306e\u5b9a\u7fa9\u3068\u6709\u9650\u7a7a\u9593\u3067\u306e\u69cb\u6210\u6cd5\u3002\u672c\u6587\u306e\u6570\u8868\u3068\u540c\u3058\u5149\u5b50\u6570\u5206\u5e03\u3092\u6301\u3064\u72b6\u614b\u306e\u6bd4\u8f03\u306f\u3001Quantum Sea\u306b\u3088\u308b\u72ec\u7acb\u306e\u89e3\u6790\u30fb\u884c\u5217\u8a08\u7b97\u3067\u3059\u3002<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>\u3042\u308b\u5149\u306e\u30e2\u30fc\u30c9\u306b\u542b\u307e\u308c\u308b\u5149\u5b50\u6570\u306e\u5e73\u5747\u304c2\u3060\u3063\u305f\u3068\u3057\u307e\u3059\u3002\u6bce\u56de\u5fc5\u305a2\u500b\u306a\u306e\u304b\u30011\u500b\u30843\u500b\u306a\u3069\u304c\u3070\u3089\u3064\u3044\u3066\u51fa\u308b\u306e\u304b\u3001\u3068\u304d\u306b\u306f\u591a\u304f\u3001\u3068\u304d\u306b\u306f\u307b\u3068\u3093\u3069\u51fa\u306a\u3044\u306e\u304b\u3002\u5e73\u5747\u3060\u3051\u3067\u306f\u3001\u3053\u306e\u9055\u3044\u306f\u898b\u3048\u307e\u305b\u3093\u3002 \u5149\u5b50\u306e\u6570\u306e\u63fa\u3089\u304e\u3092\u6bd4\u8f03\u3059\u308b\u624b [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":942,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":true,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":false,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[30],"tags":[21,259],"class_list":["post-945","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-computing","tag-21","tag-photon-statistics"],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/quantumsea.net\/wp-content\/uploads\/2026\/10\/qs-qutip-photon-g2-20261014-featured-cb0191e902da.png","_links":{"self":[{"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/posts\/945","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=945"}],"version-history":[{"count":1,"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/posts\/945\/revisions"}],"predecessor-version":[{"id":947,"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/posts\/945\/revisions\/947"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=\/wp\/v2\/media\/942"}],"wp:attachment":[{"href":"https:\/\/quantumsea.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=945"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=945"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/quantumsea.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=945"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}