反鐵磁自旋鏈中的宏觀量子效應(yīng).pdf

1、河南師范大學碩士學位論文反鐵磁自旋鏈中的宏觀量子效應(yīng)姓名：趙群超申請學位級別：碩士專業(yè)：理論物理指導(dǎo)教師：鄭公平20090401ABSTRACTTheresearchofmacroscopicquantumeffectsareconcentratedonsingledomainmagneticgrainItissignificativetoextendtheresearchtoafieldmodelThetunnelingofdomai

2、nwallsofbulkmaterialshavebeeninvestigatedinliteraturesThecollectivecoordinatesisintroducedtodemonstratethetunnelingbehaviorInfact，thetunnelingofdomainwallshasbeenreducedtoaoneparticleproblemwiththehelpofcollectivecoordin

3、atesInthispaperwestudythemacroscopicquantumeffectsofantiferromagneticspinchainbydirectlysolvingtheEuclideanfieldequationwithoutthecollectiveC00rdinatesFirstlyinthelimitofstronganisotropythemotionequationoftheNeelvectorso

4、fantiferromagneticspinchainwithbiaxialanisotropyarereducedtothesineGordonequationof11dimensionsinthesemi—classicalapproximationInstantonconfigurationof11dimensionsandthecorrespondingtunnelingamplitudeofthedegenerateorien

5、tationsofthetheNeelvectorsareobtainedTheresultshowsthatitispossibletoobservemacroscopicquantumcoherenceinafinitelengthantiferromagneticspinchainatfinitetemperatureSecondlyinthelimitoflargespin，Weworkoutthecommutationrela

6、tionsbetweentheNeelvectorsandrotationgeneratorsandobtaintheeffectiveLagrangiandensityofthequantumantiferromagneticspinchainwithbiaxialanisotropyTheinfluenceofthetopologicalphasefactoronmacroscopicquantumcoherenceofthequa

7、ntumantiferromagneticspinchainisinvestigatedTheresultsshowthatthepropertiesofthetunnelingamplitudeofthedegeneratevacuainthequantumantiferromagneticspin—chainisdeterminedbythespinquantumnumberduetOthetopologicalphasefacto