{"id":5186,"date":"2023-01-27T15:52:48","date_gmt":"2023-01-27T06:52:48","guid":{"rendered":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/?page_id=5186"},"modified":"2025-02-04T12:34:55","modified_gmt":"2025-02-04T03:34:55","slug":"maxima-%e3%81%ae-ctensor-%e3%81%a7%e3%83%95%e3%83%aa%e3%83%bc%e3%83%89%e3%83%9e%e3%83%b3%e6%96%b9%e7%a8%8b%e5%bc%8f%e3%82%92%e6%b1%82%e3%82%81%e3%82%8b","status":"publish","type":"page","link":"https:\/\/home.hirosaki-u.ac.jp\/relativity\/%e4%b8%80%e8%88%ac%e7%9b%b8%e5%af%be%e8%ab%96%e7%9a%84%e6%99%82%e7%a9%ba%e3%81%ae%e8%a1%a8%e3%81%97%e6%96%b9\/%e3%82%b3%e3%83%b3%e3%83%94%e3%83%a5%e3%83%bc%e3%82%bf%e4%bb%a3%e6%95%b0%e3%82%b7%e3%82%b9%e3%83%86%e3%83%a0%e3%81%a7%e3%82%a2%e3%82%a4%e3%83%b3%e3%82%b7%e3%83%a5%e3%82%bf%e3%82%a4%e3%83%b3%e6%96%b9\/maxima-%e3%81%ae-ctensor-%e3%81%a7%e3%83%95%e3%83%aa%e3%83%bc%e3%83%89%e3%83%9e%e3%83%b3%e6%96%b9%e7%a8%8b%e5%bc%8f%e3%82%92%e6%b1%82%e3%82%81%e3%82%8b\/","title":{"rendered":"Maxima \u306e ctensor \u3067\u30d5\u30ea\u30fc\u30c9\u30de\u30f3\u65b9\u7a0b\u5f0f\u3092\u6c42\u3081\u308b"},"content":{"rendered":"
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Maxima \u306e ctensor \u3092\u4f7f\u3063\u3066\u30d5\u30ea\u30fc\u30c9\u30de\u30f3\u30fb\u30eb\u30e1\u30fc\u30c8\u30eb\u30fb\u30ed\u30d0\u30fc\u30c8\u30bd\u30f3\u30fb\u30a6\u30a9\u30fc\u30ab\u30fc (FLRW) \u8a08\u91cf\u304b\u3089\u30a2\u30a4\u30f3\u30b7\u30e5\u30bf\u30a4\u30f3\u65b9\u7a0b\u5f0f<\/p>\n

$$G^{\\mu}_{\\ \\ \\nu} + \\Lambda \\delta^{\\mu}_{\\ \\ \\nu} = 8\\pi G T^{\\mu}_{\\ \\ \\nu}$$<\/p>\n

\u3092\u4f7f\u3063\u3066\u30d5\u30ea\u30fc\u30c9\u30de\u30f3\u65b9\u7a0b\u5f0f\u3092\u6c42\u3081\u308b\u3002<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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\u5fc5\u8981\u306a\u30d1\u30c3\u30b1\u30fc\u30b8\u306e load<\/h3>\n

\u30e1\u30c8\u30ea\u30c3\u30af\u304c\u5bfe\u89d2\u7684\u306a\u306e\u3067\uff0c\u5165\u529b\u306e\u7c21\u4fbf\u6027\u306e\u305f\u3081\u306b load(\"diag\")$<\/code> \u3057\u3066 diag()<\/code> \u3092\u4f7f\u3044\u307e\u3059\u3002<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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In\u00a0[1]:<\/div>\n
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load<\/span>(<\/span>ctensor<\/span>)<\/span>$\r\nload<\/span>(<\/span>diag<\/span>)<\/span>$\r\n<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
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\u30d5\u30ea\u30fc\u30c9\u30de\u30f3\u30fb\u30eb\u30e1\u30fc\u30c8\u30eb\u30fb\u30ed\u30d0\u30fc\u30c8\u30bd\u30f3\u30fb\u30a6\u30a9\u30fc\u30ab\u30fc\u8a08\u91cf<\/h3>\n
Wikipedia \u306e\u8a18\u8ff0\u306b\u305d\u3063\u3066\uff0cFLRW \u8a08\u91cf\u3092\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u304a\u304f\u3002\u306a\u304a\uff0cMaxima \u306e\u30ea\u30b9\u30c8\u306f 1 \u59cb\u307e\u308a\u306a\u306e\u3067\uff0c\u7b2c\u30bc\u30ed\u6210\u5206\u3092\u7b2c4\u6210\u5206\u3068\u3057\u3066\u307f\u307e\u3059\u3002<\/p>\n
$$ds^2 = a^2(t) \\left[\\frac{dr^2}{1-k r^2} + r^2 \\left(d\\theta^2 + \\sin^2\\theta\\,d\\phi^2 \\right)\\right] – dt^2 $$<\/p>\n