- Slippage and Boundary Layer Probed in an Almost Ideal Gas by a Nanomechanical Oscillator

M. Defoort et al., Phys. Rev. Lett.**113**, 136101 (2014) - Evidence for the role of normal-state electrons in nanoelectromechanical damping mechanisms at very low temperatures

K.J. Lulla et al., Phys. Rev. Lett.**110**, 177206 (2013) - Phase Diagram of the Topological Superfluid
^{3}He Confined in a Nanoscale Slab Geometry

L.V. Levitin et al., Science**340**, 841-844 (2013) - Energy and angular momentum balance in wall-bounded quantum turbulence at very low temperatures

J.J. Hosio et al., Nature Commun.**4**, 1614 (2013) - Evidence for Helical Nuclear Spin Order in GaAs Quantum Wires

C.P. Scheller et al., Phys. Rev. Lett.**112**, 066801 (2013) - Observation of a roton collective mode in a two-dimensional Fermi liquid

H. Godfrin et al., Nature**483**, 576 (2012) - The Josephson heat interferometer

F. Giazotto, M.J. Martinez-Perez, Nature**492**, 401 (2012)

## Emergent Weyl fermions and the origin of i = in quantum mechanics

*Volovik, G. E. and Zubkov, M. A.*

Conventional quantum mechanics is described in terms of complex numbers. However, all physical quantities are real. This indicates that the appearance of complex numbers in quantum mechanics may be the emergent phenomenon; i.e., complex numbers appear in the low energy description of the underlined high energy theory. We suggest a possible explanation of how this may occur. Namely, we consider the system of multicomponent Majorana fermions. There is a natural description of this system in terms of real numbers only. In the vicinity of the topologically protected Fermi point this system is described by the effective low energy theory with Weyl fermions. These Weyl fermions interact with the emergent gauge field and the emergent gravitational field.

*JETP Letters,*

**99**, 481-486 (2014)doi:

*10.1134/S0021364014080141*