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Conserved current

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25: 1124: 1291: 1234: 828: 1119:{\displaystyle j^{\mu }:={\frac {d{\mathcal {L}}}{d(\partial _{\mu })\phi }}\,{\frac {d(\delta \phi )}{d\alpha }}{\bigg |}_{\alpha =0}+{\frac {d{\mathcal {L}}}{d(\partial _{\mu })\phi ^{*}}}\,{\frac {d(\delta \phi ^{*})}{d\alpha }}{\bigg |}_{\alpha =0}=i\,\phi \,(\partial ^{\mu }\phi ^{*})-i\,\phi ^{*}\,(\partial ^{\mu }\phi )} 683: 520: 785: 240: 572: 730: 601: 172: 289: 823: 1332: 54: 126: 468: 1275: 195: 735: 1325: 1215: 1194: 416:, as the existence of a conserved current implies the existence of a symmetry. Conserved currents play an important role in the theory of 200: 1268: 1376: 1318: 1167: 544: 76: 378: 1371: 1361: 1158: 1261: 417: 1356: 37: 47: 41: 33: 1135: 335: 688: 1351: 134: 58: 364: 462: 351: 326: 303: 98: 1206:
Peskin, Michael E.; Schroeder, Daniel V. (1995). "Chapter I.2.2. Elements of Classical Field Theory".
1140: 405: 245: 1298: 678:{\displaystyle {\mathcal {L}}=\partial _{\mu }\phi ^{*}\,\partial ^{\mu }\phi +V(\phi ^{*}\,\phi )} 421: 401: 330: 323: 319: 307: 129: 1186: 790: 412:
of some quantity in the system under study. In practical terms, all conserved currents are the
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The equation would apply equally to masses (or other conserved quantities), where the word
413: 394: 390: 197:, large enough to have no net currents through its surface, leads to the conservation law 1180: 1290: 1233: 180: 1345: 386: 383: 441: 299: 515:{\displaystyle {\frac {\partial \rho }{\partial t}}+\nabla \cdot \mathbf {J} =0} 433: 425: 409: 360: 174:. The continuity equation represents a conservation law, hence the name. 16:
Concept in physics and mathematics that satisfies the continuity equation
393:- the continuous phase angle symmetry of the wave function implies the 90: 420:, as the existence of a conserved current points to the existence of 347: 408:
connects the existence of a conserved current to the existence of a
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the gauge fields couple to conserved currents. For example, the
1162:(2nd ed.). Reading, MA: Addison-Wesley. pp. 588–596. 18: 432:. The conservation law is expressed as the vanishing of a 4- 363:- the continuous translational symmetry of space implies the 946: 853: 607: 350:- the continuous translational symmetry of time implies the 780:{\displaystyle \phi \mapsto \phi '=\phi \,e^{i\alpha }\,.} 177:
Indeed, integrating the continuity equation over a volume
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Conserved currents play an extremely important role in
248: 831: 738: 604: 547: 471: 235:{\displaystyle {\frac {\partial }{\partial t}}Q=0\;,} 203: 183: 137: 107: 1118: 817: 779: 724: 677: 566: 514: 339:. Examples of canonical conjugate quantities are: 283: 234: 189: 166: 120: 1025: 918: 46:but its sources remain unclear because it lacks 732:is invariant under the symmetry transformation 567:{\displaystyle \mathbf {J} =\rho \mathbf {v} } 333:for the conserved current is a statement of a 1326: 1269: 8: 725:\phi :\mathbb {R} ^{n+1}\mapsto \mathbb {C} 1333: 1319: 1276: 1262: 1185:(Third ed.). Prentice Hall. pp.  228: 167:{\displaystyle \partial _{\mu }j^{\mu }=0} 1126:which satisfies the continuity equation. 1104: 1096: 1090: 1085: 1070: 1060: 1052: 1048: 1030: 1024: 1023: 1002: 986: 985: 976: 963: 945: 944: 938: 923: 917: 916: 886: 885: 870: 852: 851: 845: 836: 830: 773: 764: 759: 737: 719: 718: 703: 699: 698: 668: 662: 640: 635: 629: 619: 606: 605: 603: 559: 548: 546: 532:electric charge density (in units of C/m) 501: 472: 470: 269: 259: 247: 204: 202: 182: 152: 142: 136: 112: 106: 77:Learn how and when to remove this message 1208:An Introduction to Quantum Field Theory 318:Conserved current is the flow of the 7: 1287: 1285: 1230: 1228: 314:Conserved quantities and symmetries 1305:. You can help Knowledge (XXG) by 1248:. You can help Knowledge (XXG) by 1101: 1057: 960: 867: 637: 616: 495: 483: 475: 461:, for example, in the notation of 440:forms the zeroth component of the 210: 206: 139: 14: 424:, which are required to define a 1289: 1232: 560: 549: 502: 379:conservation of angular momentum 23: 1182:Introduction to electrodynamics 578:as the velocity of the charges. 395:conservation of electric charge 284:{\textstyle Q=\int _{V}j^{0}dV} 1113: 1097: 1076: 1053: 1008: 992: 969: 956: 901: 892: 876: 863: 742: 715: 672: 655: 418:partial differential equations 377:symmetry of space implies the 1: 586:is substituted for the words 825:we find the Noether current 322:of a quantity possessing a 1393: 1284: 1227: 1179:David J Griffiths (1999). 1136:Conservation law (physics) 685:of a complex scalar field 308:conserved electric current 1377:Theoretical physics stubs 818:\delta \phi =\phi '-\phi 365:conservation of momentum 121:{\displaystyle j^{\mu }} 32:This article includes a 598:The Lagrangian density 61:more precise citations. 1372:Electromagnetism stubs 1362:Conservation equations 1244:-related article is a 1120: 819: 781: 726: 679: 568: 516: 459:conservation of charge 352:conservation of energy 327:translational symmetry 285: 236: 191: 168: 122: 1121: 820: 782: 727: 680: 569: 517: 304:electromagnetic field 286: 237: 192: 169: 128:, that satisfies the 123: 829: 791: 736: 689: 602: 594:Complex scalar field 545: 469: 436:, where the Noether 246: 201: 181: 135: 105: 1357:Theoretical physics 1299:theoretical physics 1297:This article about 1159:Classical Mechanics 463:Maxwell's equations 422:constants of motion 402:theoretical physics 331:continuity equation 320:canonical conjugate 130:continuity equation 1154:Goldstein, Herbert 1116: 777: 675: 564: 512: 293:conserved quantity 281: 232: 187: 164: 118: 34:list of references 1314: 1313: 1257: 1256: 1217:978-0-201-50397-5 1196:978-0-13-805326-0 1141:Noether's theorem 1020: 983: 913: 883: 490: 430:integrable system 406:Noether's theorem 373:- the continuous 217: 190:{\displaystyle V} 95:conserved current 87: 86: 79: 1384: 1352:Electromagnetism 1335: 1328: 1321: 1293: 1286: 1278: 1271: 1264: 1242:electromagnetism 1236: 1229: 1221: 1200: 1173: 1125: 1123: 1122: 1117: 1109: 1108: 1095: 1094: 1075: 1074: 1065: 1064: 1041: 1040: 1029: 1028: 1021: 1019: 1011: 1007: 1006: 987: 984: 982: 981: 980: 968: 967: 951: 950: 949: 939: 934: 933: 922: 921: 914: 912: 904: 887: 884: 882: 875: 874: 858: 857: 856: 846: 841: 840: 824: 822: 821: 816: 809: 786: 784: 783: 778: 772: 771: 752: 731: 729: 728: 723: 722: 714: 713: 702: 684: 682: 681: 676: 667: 666: 645: 644: 634: 633: 624: 623: 611: 610: 573: 571: 570: 565: 563: 552: 521: 519: 518: 513: 505: 491: 489: 481: 473: 453:Electromagnetism 414:Noether currents 371:angular momentum 336:conservation law 290: 288: 287: 282: 274: 273: 264: 263: 241: 239: 238: 233: 218: 216: 205: 196: 194: 193: 188: 173: 171: 170: 165: 157: 156: 147: 146: 127: 125: 124: 119: 117: 116: 82: 75: 71: 68: 62: 57:this article 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CRC Press. 1209: 1204: 1203: 1198: 1192: 1188: 1184: 1183: 1177: 1176: 1171: 1169:0-201-02918-9 1165: 1161: 1160: 1155: 1151: 1150: 1146: 1142: 1139: 1137: 1134: 1133: 1129: 1127: 1110: 1105: 1091: 1087: 1082: 1079: 1071: 1067: 1061: 1049: 1045: 1042: 1037: 1034: 1031: 1016: 1013: 1003: 999: 995: 989: 977: 973: 964: 953: 941: 935: 930: 927: 924: 909: 906: 898: 895: 889: 879: 871: 860: 848: 842: 837: 833: 813: 810: 806: 803: 799: 796: 793: 774: 768: 765: 761: 756: 753: 749: 746: 739: 710: 707: 704: 694: 691: 669: 663: 659: 652: 649: 646: 641: 630: 626: 620: 612: 593: 591: 589: 585: 577: 556: 553: 541: 537: 534: 531: 527: 526: 525: 522: 509: 506: 498: 492: 486: 478: 464: 460: 452: 447: 445: 443: 439: 435: 431: 427: 423: 419: 415: 411: 407: 403: 396: 392: 388: 385: 384:Wave function 382: 380: 376: 372: 368: 366: 362: 358: 355: 353: 349: 345: 342: 341: 340: 338: 337: 332: 328: 325: 321: 313: 311: 309: 305: 301: 296: 294: 278: 275: 270: 266: 260: 256: 252: 249: 229: 225: 222: 219: 213: 184: 175: 161: 158: 153: 149: 143: 131: 113: 109: 100: 96: 92: 81: 78: 70: 67:December 2009 60: 56: 50: 49: 43: 39: 35: 30: 21: 20: 1307:expanding it 1296: 1250:expanding it 1239: 1224: 1207: 1181: 1157: 597: 587: 583: 581: 575: 539: 535: 529: 523: 458: 456: 428:and thus an 399: 374: 334: 317: 297: 176: 94: 88: 73: 64: 53:Please help 45: 59:introducing 1346:Categories 1147:References 434:divergence 404:, because 375:rotational 369:Space and 324:continuous 1111:ϕ 1106:μ 1102:∂ 1092:∗ 1088:ϕ 1080:− 1072:∗ 1068:ϕ 1062:μ 1058:∂ 1050:ϕ 1032:α 1017:α 1004:∗ 1000:ϕ 996:δ 978:∗ 974:ϕ 965:μ 961:∂ 925:α 910:α 899:ϕ 896:δ 880:ϕ 872:μ 868:∂ 838:μ 814:ϕ 811:− 804:ϕ 797:ϕ 794:δ 787:Defining 769:α 757:ϕ 747:ϕ 743:↦ 740:ϕ 716:↦ 692:ϕ 670:ϕ 664:∗ 660:ϕ 647:ϕ 642:μ 638:∂ 631:∗ 627:ϕ 621:μ 617:∂ 557:ρ 528:ρ is the 499:⋅ 496:∇ 484:∂ 479:ρ 476:∂ 442:4-current 426:foliation 257:∫ 211:∂ 207:∂ 154:μ 144:μ 140:∂ 114:μ 1367:Symmetry 1156:(1980). 1130:See also 807:′ 750:′ 448:Examples 410:symmetry 361:momentum 1187:356–357 590:above. 538:is the 329:. The 291:is the 99:current 91:physics 55:improve 1214:  1193:  1166:  524:where 438:charge 348:energy 242:where 1301:is a 1240:This 574:with 387:phase 357:Space 97:is a 40:, or 1303:stub 1246:stub 1212:ISBN 1191:ISBN 1164:ISBN 584:mass 530:free 457:The 389:and 359:and 346:and 344:Time 298:In 89:In 1348:: 1189:. 843::= 465:, 444:. 310:. 295:. 101:, 93:a 44:, 36:, 1334:e 1327:t 1320:v 1309:. 1277:e 1270:t 1263:v 1252:. 1220:. 1199:. 1172:. 1114:) 1098:( 1083:i 1077:) 1054:( 1046:i 1043:= 1038:0 1035:= 1026:| 1014:d 1009:) 993:( 990:d 970:) 957:( 954:d 947:L 942:d 936:+ 931:0 928:= 919:| 907:d 902:) 893:( 890:d 877:) 864:( 861:d 854:L 849:d 834:j 800:= 775:. 766:i 762:e 754:= 720:C 711:1 708:+ 705:n 700:R 695:: 673:) 656:( 653:V 650:+ 613:= 608:L 576:v 561:v 554:= 550:J 536:J 510:0 507:= 503:J 493:+ 487:t 279:V 276:d 271:0 267:j 261:V 253:= 250:Q 230:, 226:0 223:= 220:Q 214:t 185:V 162:0 159:= 150:j 110:j 80:) 74:( 69:) 65:( 51:.

Index

list of references
related reading
external links
inline citations
improve
introducing
Learn how and when to remove this message
physics
current
continuity equation
conserved quantity
gauge theories
electromagnetic field
conserved electric current
canonical conjugate
continuous
translational symmetry
continuity equation
conservation law
Time
energy
conservation of energy
Space
momentum
conservation of momentum
angular momentum
conservation of angular momentum
Wave function
phase
electric charge

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