Metastable vacuum decay and θ dependence in gauge theory. Deformed QCD as a toy model

Bhoonah, Amit; Thomas, Evan; Zhitnitsky, Ariel R.

doi:10.1016/j.nuclphysb.2014.11.007

Cited by 21 publications

(38 citation statements)

References 49 publications

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“…A similar conclusion also follows from the holographic description of QCD as originally discussed in [22]. Furthermore, the metastable vacuum states can be explicitly constructed in a weakly coupled "deformed QCD" model [23].…”

Section: Metastable Quantum States In the Maxwell Systemsupporting

confidence: 64%

“…An explicit manifestation of this "non-dispersive" nature of the vacuum energy in the model considered in the present work is the "wrong sign" of the kinetic term in the effective Lagrangians describing the dynamics of the auxiliary no-propagating fields (23,31). This "wrong sign" has exactly the same nature as the conjectured Veneziano ghost introduced in QCD to resolve the so-called U (1) problem, see Footnote 4 for a few comments on this matter.…”

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confidence: 91%

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Topological Casimir effect in a quantum LC circuit: Real-time dynamics

Yao

Zhitnitsky

2017

Phys. Rev. D

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We study novel contributions to the partition function of the Maxwell system defined on a small compact manifold M with nontrivial mappings π1[U (1)] ∼ = Z. These contributions cannot be described in terms of conventional physical propagating photons with two transverse polarizations, and instead emerge as a result of tunneling transitions between topologically different but physically identical vacuum winding states. We argue that if the same system is considered in the background of a small external time-dependent E&M field, then real physical photons will be emitted from the vacuum, similar to the dynamical Casimir effect (DCE) where photons are radiated from the vacuum due to time-dependent boundary conditions. The fundamental technical difficulty for such an analysis is that the radiation of physical photons on mass shell is inherently a realtime Minkowskian phenomenon while the vacuum fluctuations interpolating between topological |k sectors rest upon a Euclidean instanton formulation. We overcome this obstacle by introducing auxiliary topological fields which allows for a simple analytical continuation between Minkowski and Euclidean descriptions, and develop a quantum mechanical technique to compute these effects.We also propose an experimental realization of such small effects using a microwave cavity with appropriate boundary conditions. Finally, we comment on the possible cosmological implications of this effect.

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Section: Metastable Quantum States In the Maxwell Systemsupporting

confidence: 64%

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confidence: 91%

Topological Casimir effect in a quantum LC circuit: Real-time dynamics

Yao

Zhitnitsky

2017

Phys. Rev. D

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“…where h is a new parameter and the subscript "td" stands for "trace deformation" (higher powers of P ( x) have also to be added in SU (N c ) theories with N c > 3, see [6]). Several works followed this approach, but possible alternative, like the introduction of adjoint fermions or the use of non-thermal boundary conditions, have also been proposed [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. In the present work we will restrict ourselves to the case of the deformation in Eq.…”

Section: Introductionmentioning

confidence: 99%

θ dependence in trace deformed SU(3) Yang-Mills theory: A lattice study

2018

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In this paper we investigate, by means of numerical lattice simulations, the topological properties of the trace deformed SU (3) Yang-Mills theory defined on S1 × R 3 . More precisely, we evaluate the topological susceptibility and the b2 coefficient (related to the fourth cumulant of the topological charge distribution) of this theory for different values of the lattice spacing and of the compactification radius. In all the cases we find results in good agreement with the corresponding ones of the standard SU (3) Yang-Mills theory on R

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“…In a field theory with a topological Θ-angle in the Lagrangian, subtle effects may arise at certain values of the Θ-angle [13][14][15][16]. For example, at Θ = π in SU(2) gauge theory there is a cancellation of leading order saddle contribution to the mass gap [14].…”

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confidence: 99%

Hidden Topological Angles in Path Integrals

et al. 2015

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We demonstrate the existence of hidden topological angles (HTAs) in a large class of quantum field theories and quantum mechanical systems. HTAs are distinct from theta-parameters in the lagrangian. They arise as invariant angle associated with saddle points of the complexified path integral and their descent manifolds (Lefschetz thimbles). Physical effects of HTAs become most transparent upon analytic continuation in n f to non-integer number of flavors, reducing in the integer n f limit to a Z 2 valued phase difference between dominant saddles. In N = 1 super Yang-Mills theory we demonstrate the microscopic mechanism for the vanishing of the gluon condensate. The same effect leads to an anomalously small condensate in a QCD-like SU(N) gauge theory with fermions in the two-index representation. The basic phenomenon is that, contrary to folklore, the gluon condensate can receive both positive and negative contributions in a semi-classical expansion. In quantum mechanics, a HTA leads to a difference in semi-classical expansion of integer and half-integer spin particles.Introduction. Providing a non-perturbative continuum definition of the path integral in quantum field theory is a challenging but important problem [1]. There is growing evidence that, if an ordinary integral or a path integral admits a Lefschetz-thimble decomposition [2,3] or resurgent transseries expansion [4][5][6][7][8][9][10][11][12] then either of these methods gives this long-sought non-perturbative definition. If this is indeed the case, then we expect that these new methods will provide new and deep insight into quantum field theory and quantum mechanics formulated in terms of path integrals. In this article we introduce a new phenomenon of this kind, the appearance of hidden topological angles (HTAs).The main prescription associated with the Lefschetzthimble decomposition or the resurgent expansion is the following: Even if an ordinary integral or a path integral is formulated over real fields, the natural space that the critical points (saddles) ρ σ live in is the complexification of the original space of fields. However, the dimension of the crit-

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Metastable vacuum decay and θ dependence in gauge theory. Deformed QCD as a toy model

Cited by 21 publications

References 49 publications

Topological Casimir effect in a quantum LC circuit: Real-time dynamics

Topological Casimir effect in a quantum LC circuit: Real-time dynamics

θ dependence in trace deformed SU(3) Yang-Mills theory: A lattice study

Hidden Topological Angles in Path Integrals

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