Breaking Terms Research Articles

SYMPLECTIC NO-CORE SHELL MODEL

The symplectic no-core shell model (Sp-NCSM) is described. The theory is applied to a study of the structure of 12 C and 16 O . Results from a full 6ħΩ NCSM calculation for low-lying states in these nuclei using a realistic nucleon-nucleon interaction are found to project at approximately the 90% level onto a few of the leading 0 p -0 h and 2 p -2 h symplectic representations. The results are nearly independent of the oscillator strength parameter and whether bare or renormalized effective interactions are used in the analysis. The Sp-NCSM model space is typically only a very small fraction (under 1%) of the NCSM space, and grows slowly with increasing ħΩ. The comparisons with NCSM results suggest either the effective nucleon-nucleon interaction possesses a heretofore unappreciated symmetry, namely Sp(3,R) and the complementary (spin-isospin) supermultiplet symmetry, or the nuclear many-body system acts as a filter that allows the symplectic symmetry to propagate in a coherent way into the many-body dynamics while tending to dampen out symplectic symmetry breaking terms. Also, since the Sp-NCSM is a multi-ħΩ generalization of the Elliott SU (3) model, the results obtained to date reaffirm the relevance of SU (3) to atomic nuclei.

Polarized polariton condensates and coupledXYmodels

Microcavity polaritons, which at low temperatures can condense to a macroscopic coherent state, possess a polarization degree of freedom. This paper discusses the phase diagram of such a system, showing the boundaries between differently polarized condensates. The Bogoliubov approximation is shown to have problems in describing the transition between differently polarized phases; the Hartree-Fock-Popov approximation performs better, and compares well to exact results that can be used in the limit where the left- and right-circular polarization states decouple. The effects on the phase boundary of various symmetry breaking terms present in real microcavities are also considered.

Effective particle kinematics from quantum gravity

Particles propagating in de Sitter spacetime can be described by the topological BF $\mathsf{S}\mathsf{O}(4,1)$ theory coupled to point charges. Gravitational interaction between them can be introduced by adding to the action a symmetry breaking term, which reduces the local gauge symmetry down to $\mathsf{S}\mathsf{O}(3,1)$, and which can be treated as a perturbation. In this paper we focus solely on topological interactions which correspond to zeroth order in this perturbative expansion. We show that in this approximation the system is effectively described by the $\mathsf{S}\mathsf{O}(4,1)$ Chern-Simons theory coupled to particles and living on the three-dimensional boundary of spacetime. Then, using Alekseev-Malkin construction we find the effective theory of particles kinematics. We show that the particles action contains standard kinetic terms and the deformation shows up in the presence of interaction terms. The strength of the interactions is proportional to deformation parameter, identified with Planck mass scale.

Sixties

Sixties

Pion Pair Condensed Nuclear Matter in the Extended Linear Sigma Model

The linear sigma model with vector meson contributions, higher-power chiral loop terms, and additional chiral symmetry breaking terms is applied to nuclear matter at a finite nuclear density. Nonzero classical pion fields are assumed where the pion effective mass squared is less than zero for sigma condensed nuclear matter. It is shown that, in these regions, pion pair condensed nuclear matter has less energy than sigma condensed nuclear matter without classical pion fields. Pion condensed nuclear matter can have a minimum energy of −16.3 MeV and an incompressibility of about 300 MeV at a normal nuclear density ρ0 = 0.153 /fm3, without the introduction of additional chiral symmetry breaking terms.

Moduli stabilization and supersymmetry breaking in deflected mirage mediation

We present a model of supersymmetry breaking in which the contributions from gravity/modulus, anomaly, and gauge mediation are all comparable. We term this scenario ``deflected mirage mediation'', which is a generalization of the KKLT-motivated mirage mediation scenario to include gauge mediated contributions. These contributions deflect the gaugino mass unification scale and alter the pattern of soft parameters at low energies. In some cases, this results in a gluino LSP and light stops; in other regions of parameter space, the LSP can be a well-tempered neutralino. We demonstrate explicitly that competitive gauge-mediated terms can naturally appear within phenomenological models based on the KKLT setup by addressing the stabilization of the gauge singlet field which is responsible for the masses of the messenger fields. For viable stabilization mechanisms, the relation between the gauge and anomaly contributions is identical in most cases to that of deflected anomaly mediation, despite the presence of the K?hler modulus. Turning to TeV scale phenomenology, we analyze the renormalization group evolution of the supersymmetry breaking terms and the resulting low energy mass spectra. The approach sets the stage for studies of such mixed scenarios of supersymmetry breaking at the LHC.

SEQUESTERED UPLIFTING AND THE PATTERN OF SOFT SUPERSYMMETRY BREAKING TERMS

We examine the pattern of soft supersymmetry breaking terms in moduli stabilization, where an uplifting potential is provided by spontaneously broken supersymmetry in a generic sequestered sector. From stationary conditions, we derive the relation between moduli F-term vacuum expectation values which does not depend on the details of sequestered uplifting. This moduli F-term relation that reflects the sequestering structure is crucial for identifying the dominant source of soft terms of visible fields.

On quantum effects in soft leptogenesis

It has been recently shown that quantum Boltzmann equations may be relevant forleptogenesis. Quantum effects, which lead to a time-dependent CP asymmetry,have been shown to be particularly important for resonant leptogenesis when theasymmetry is generated by the decay of two nearly degenerate states. In this work weinvestigate the impact of the use of quantum Boltzmann equations in the frameworkof ‘soft leptogenesis’ in which supersymmetry soft breaking terms give a smallmass splitting between the CP-even and CP-odd right-handed sneutrino states ofa single generation and provide the CP-violating phase to generate the leptonasymmetry.

Entanglement, quantum phase transition and fixed-point bifurcation in the N-atom Jaynes–Cummings model with an additional symmetry breaking term

In the present work we analyze the quantum phase transition (QPT) in the N-atom Jaynes–Cummings model (NJCM) with an additional symmetry breaking interaction term in the Hamiltonian. We show that depending on the type of symmetry breaking term added the transition order can change or not and also the fixed point associated to the classical analogue of the Hamiltonian can bifurcate or not. We present two examples of symmetry broken Hamiltonians and discuss based on them, the interconnection between the transition order, appearance of bifurcation and the behavior of the entanglement.

Dirac leptogenesis in extended nMSSM

We show that a version of the nearly Minimal Supersymmetric Standard Model (nMSSM), extended only in the singlet sector to include the additional superfields of right-handed neutrinos and very heavy Dirac particles conserving B−L, admits a viable scenario for Dirac leptogenesis and naturally small Dirac neutrino masses. The origin of the (B−L)-conserving high singlet neutrino scale and the desired supersymmetry breaking terms is associated with dynamical supersymmetry breaking in the hidden sector.

Flavoured soft leptogenesis

We study the impact of flavour in ``soft leptogenesis'' (leptogenesis induced by soft supersymmetry breaking terms). We address the question of how flavour effects can affect the region of parameters in which successful soft leptogenesis induced by CP violation in the right-handed sneutrino mixing is possible. We find that for decays which occur in the intermediate to strong washout regimes for all flavours, the produced total $B-L$ asymmetry can be up to a factor ${\cal O}(30)$ larger than the one predicted with flavour effects being neglected. This enhancement, permits slightly larger values of the required lepton violating soft bilinear term.

Current-driven quantum criticality in itinerant electron ferromagnets

We determine the effect of an in-plane current flow on the critical properties of a 2d itinerant electron system near a ferromagnetic-paramagnetic quantum critical point. We study a model in which a nonequilibrium steady state is established as a result of exchange of particles and energy with an underlying substrate. the current $\vec{j}$ gives rise not only to an effective temperature equal to the voltage drop over a distance of order the mean free path, but also to symmetry breaking terms of the form $\vec{j}\cdot \vec{nabla}$ in the effective action. The effect of the symmetry breaking on the fluctuational and critical properties is found to be small although (in agreement with previous results) if rotational degrees of freedom are important, the current can make the classically ordered state dynamically unstable.

Soft supersymmetry breaking terms fromD4×Z2lepton flavor symmetry

We study the supersymmetric model with ${D}_{4}\ifmmode\times\else\texttimes\fi{}{Z}_{2}$ lepton flavor symmetry. We evaluate soft supersymmetry breaking terms, i.e., soft slepton masses and A-terms, which are predicted in the ${D}_{4}$ flavor model. We consider constraints due to experiments of flavor-changing neutral current processes.

Intimate relations between electronic nematic, d-density wave and d-wave superconductingstates

This paper consists of two important theoretical observations on the interplay betweenl = 2 condensates; d-density wave (ddw), electronic nematic and d-wave superconducting states. (1) Thereis SO(4) invariance at a transition between the nematic and d-wave superconducting states. Thenematic and d-wave pairing operators can be rotated into each other by pseudospinSU(2) generators, which are s-wave pairing and electron density operators.The difference between the current work and the previousO(4) symmetry at a transition between the ddw and d-wave superconducting states (Nayak 2000Phys. Rev. B 62 R6135) is presented. (2) The nematic and ddw operators transform intoeach other under a unitary transformation. Thus, when a Hamiltonian is invariant undersuch a transformation, the two states are exactly degenerate. The competition between thenematic and ddw states in the presence of a degeneracy breaking term is discussed.

Mirage pattern from the heterotic string

We provide a simple example of dilaton stabilization in the framework of heterotic string theory. It requires a gaugino condensate and an uplifting sector similar to the one postulated in type IIB string theory. Its signature is a hybrid mediation of supersymmetry breakdown with a variant of a mirage pattern for the soft breaking terms. The setup is suited for the discussion of heterotic minimal supersymmetric standard model candidates.

Publisher’s Note: Einsteinian gravity from BRST quantization of a topological action [Phys. Rev. D77, 084020 (2008)

The curvature-squared model of gravity, in the affine form proposed by Weyl and Yang, is deduced from a topological action in 4D. More specifically, we start from the Pontrjagin (or Euler) invariant. Using the BRST antifield formalism with a double duality gauge fixing, we obtain a consistent quantization in spaces of double dual curvature as classical instanton type background. However, exact vacuum solutions with double duality properties exhibit a `vacuum degeneracy'. By modifying the duality via a scale breaking term, we demonstrate that only Einstein's equations with an induced cosmological constant emerge for the topology of the macroscopic background. This may have repercussions on the problem of `dark energy' as well as `dark matter' modeled by a torsion induced quintaxion.

Einsteinian gravity from BRST quantization of a topological action

In order to deduce Einsteinian gravity from a topological action, we start from the metric-free Pontrjagin invariant in four dimensions. Using the Becchi-Rouet-Stora-Tyutin antifield formalism with a double duality gauge fixing, we obtain a consistent quantization in spaces of double dual curvature. They correspond to classical instanton type solutions of a curvature-squared model of gravity, in the affine form proposed already by Weyl and Yang. However, the exact vacuum solutions with double duality properties exhibit a ``vacuum degeneracy.'' By modifying the duality of the curvature via scale breaking terms, we demonstrate that only Einstein's equations with an induced cosmological constant of partially topological origin emerge for the macroscopic ``background.''

Dynamically sequestered F-term uplifting in extra dimension

We study concretely several issues altogether, moduli stabilization, the dynamical supersymmetry (SUSY) breaking, the uplifting of SUSY anti-de Sitter (AdS) vacuum and the sequestering of hidden sector, in a simple supergravity model with a single extra dimension. The sequestering is achieved dynamically by a wavefunction localization in extra dimension. The expressions for the visible sector soft SUSY breaking terms as well as the hidden sector potential are shown explicitly in our model. We find that the tree-level soft scalar mass and the A-term can be suppressed at a SUSY breaking Minkowski minimum where the radius modulus is stabilized, while gaugino masses would be a mirage type.

Measuring smuon-selectron mass splitting at the CERN LHC and patterns of supersymmetry breaking

With sufficient data, CERN LHC experiments can constrain the smuon-selectron mass splitting through differences in the dielectron and dimuon edges from supersymmetry (SUSY) cascade decays. We study the sensitivity of the LHC to this mass splitting, which within minimal supergravity may be constrained down to $\mathcal{O}({10}^{\ensuremath{-}4})$ for $30\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity. Over substantial regions of SUSY breaking parameter space the fractional edge splitting can be significantly enhanced over the fractional mass splitting. Within models where the selectron and smuon are constrained to be universal at a high scale, edge splittings up to a few percent may be induced by renormalization group effects and may be significantly discriminated from zero. The edge splitting provides important information about high-scale SUSY breaking terms and should be included in any fit of LHC data to high-scale models.

PeV scale Left–Right symmetry and baryon asymmetry of the Universe

We study the cosmology of two versions of supersymmetric Left–Right symmetric model. The scale of the B – L symmetry breaking in these models is naturally low, 10 4 – 10 6 GeV . Spontaneous breakdown of parity is accompanied by a first order phase transition. We simulate the domain walls of the phase transition and show that they provide requisite conditions, specifically, CP violating phase needed for leptogenesis. Additionally soft resonant leptogenesis is conditionally viable in the two models considered. Some of the parameters in the soft supersymmetry breaking terms are shown to be constrained from these considerations. It is argued that the models may be testable in upcoming collider and cosmology experiments.