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Kieburg, M. ; Verbaarschot, J. J. M. ; Wettig, T.

Dirac spectrum and chiral condensate for QCD at fixed θ angle

Kieburg, M., Verbaarschot, J. J. M. und Wettig, T. (2019) Dirac spectrum and chiral condensate for QCD at fixed θ angle. Physical Review D 99 (7), 074515-1-074515-21.

Veröffentlichungsdatum dieses Volltextes: 06 Apr 2021 13:51
Artikel
DOI zum Zitieren dieses Dokuments: 10.5283/epub.45507


Zusammenfassung

We analyze the mass dependence of the chiral condensate for QCD at nonzero theta angle and find that in general the discontinuity of the chiral condensate is not on the support of the Dirac spectrum. To understand this behavior we decompose the spectral density and the chiral condensate into contributions from the zero modes, the quenched part, and a remainder which is sensitive to the fermion ...

We analyze the mass dependence of the chiral condensate for QCD at nonzero theta angle and find that in general the discontinuity of the chiral condensate is not on the support of the Dirac spectrum. To understand this behavior we decompose the spectral density and the chiral condensate into contributions from the zero modes, the quenched part, and a remainder which is sensitive to the fermion determinant and is referred to as the dynamical part. We obtain general formulas for the contributions of the zero modes. Expressions for the quenched part, valid for an arbitrary number of flavors, and for the dynamical part, valid for one and two flavors, are derived in the microscopic domain of QCD. We find that at nonzero theta angle the quenched and dynamical parts of the Dirac spectral density are strongly oscillating with an amplitude that increases exponentially with the volume V and a period of order of 1/V. The quenched part of the chiral condensate becomes exponentially large at theta not equal 0, but this divergence is canceled by the contribution from the zero modes. The oscillatory behavior of the dynamical part of the density is essential for moving the discontinuity of the chiral condensate away from the support of the Dirac spectrum. As important by-products of this work we obtain analytical expressions for the microscopic spectral density of the Dirac operator at nonzero theta angle for both one- and two-flavor QCD with nonzero quark masses.



Beteiligte Einrichtungen


Details

DokumentenartArtikel
Titel eines Journals oder einer ZeitschriftPhysical Review D
Verlag:AMER PHYSICAL SOC
Ort der Veröffentlichung:COLLEGE PK
Band:99
Nummer des Zeitschriftenheftes oder des Kapitels:7
Seitenbereich:074515-1-074515-21
Datum30 April 2019
InstitutionenPhysik > Institut für Theoretische Physik > Lehrstuhl Professor Braun > Arbeitsgruppe Tilo Wettig
Identifikationsnummer
WertTyp
10.1103/PhysRevD.99.074515DOI
Stichwörter / KeywordsOPERATOR; INSTANTONS; PHASE;
Dewey-Dezimal-Klassifikation500 Naturwissenschaften und Mathematik > 530 Physik
StatusVeröffentlicht
BegutachtetJa, diese Version wurde begutachtet
An der Universität Regensburg entstandenJa
URN der UB Regensburgurn:nbn:de:bvb:355-epub-455076
Dokumenten-ID45507

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