Related papers: Fermionic quartet and vestigial gravity
A hallmark of the phase diagrams of quantum materials is the existence of multiple electronic ordered states, which, in many cases, are not independent competing phases, but instead display a complex intertwinement. In this review, we focus…
The paper is devoted to the memory of Dmitry Diakonov. We discuss gravity emerging in the fermionic vacuum as suggested by Diakonov 10 years ago in his paper "Towards lattice-regularized Quantum Gravity". Gravity emerges in the phase…
An electronic nematic order that originates from superconducting fluctuation but persists above the superconducting transition temperature is often referred to as a vestigial nematic phase. Such a vestigial order belongs to the broader…
Electronically ordered states that break multiple symmetries can melt in multiple stages, similarly to liquid crystals. In the partially-melted phases, known as vestigial phases, a bilinear made out of combinations of the multiple…
The quantum phase transition in iron-based superconductors with 'half-Dirac' node at the electron Fermi surface as a $T=0$ structural phase transition described in terms of nematic order is discussed. An effective low energy theory that…
The underdoped phase diagram of the iron-based superconductors exemplifies the complexity common to many correlated materials. Indeed, multiple ordered states that break different symmetries but display comparable transition temperatures…
We study the quantum critical point between the fermionic $\nu=8$ quantum Hall state and the bosonic $\nu=2$ quantum Hall state of Cooper pairs. Our study is motivated by the composite fermion construction for the daughter states of…
We address the quantum-critical behavior of a two-dimensional itinerant ferromagnetic systems described by a spin-fermion model in which fermions interact with close to critical bosonic modes. We consider Heisenberg ferromagnets, Ising…
We discuss a {\em family} of planar (two-dimensional) systems with the following phase strucure: a Fermi liquid, which goes by a second order transition (with non classical exponent even in mean-field) to an intermediate, inhomogeneous…
Electron pairing at low temperatures leads to superconductivity. A fundamental question is whether more complex states - characterized by order in four-electron composite objects, termed electron quadrupling or composite order - can exist…
The semimetal-superconductor quantum phase transition on the two-dimensional (2D) surface of a 3D topological insulator is conjectured to exhibit an emergent $\mathcal{N}=2$ supersymmetry, based on a renormalization group (RG) analysis at…
Quantum states of a novel Bose-Einstein condensate, in which both fermion-pair and exciton condensations are simultaneously present, have recently been realized theoretically in a model Hamiltonian system. Here we identify quantum phase…
When a metal undergoes continuous quantum phase transition, the correlation length diverges at the critical point and the quantum fluctuation of order parameter behaves as a gapless bosonic mode. Generically, the coupling of this boson to…
In gravitation theory, a fermion field must be regarded only in a pair with a certain tetrad gravitational field. These pairs can be represented by sections of the composite spinor bundle $S\to\Si\to X^4$ where values of gravitational…
The Schwinger-boson theory of the frustrated square lattice antiferromagnet yields a stable, gapped $\mathbb{Z}_2$ spin liquid ground state with time-reversal symmetry, incommensurate spin correlations and long-range Ising-nematic order. We…
In a background of a very strong magnetic field a quantum vacuum may turn into a new phase characterized by anisotropic electromagnetic superconductivity. The phase transition should take place at a critical magnetic field of the hadronic…
In the standard quantum electrodynamics (QED), the fermionic vacuum is a continuum of randomly created and annihilated virtual electron-positron pairs. In this case, in the strong electromagnetic fields, vacuum creation of real…
We discuss two scenarios of emergent gravity. In one of them the quantum vacuum is considered as superplastic crystal, and the effective gravity describes the dynamical elastic deformations of this crystal. In the other one the…
For intermediate Coulomb energy to Fermi energy ratios $r_s$, spinless fermions in a random potential form a new quantum phase which is different from the Fermi glass and the Wigner crystal. From a numerical study of small clusters, we show…
We study fermionic topological phases using the technique of fermion condensation. We give a prescription for performing fermion condensation in bosonic topological phases which contain a fermion. Our approach to fermion condensation can…