Chiral matters*

The properties of materials, including their structure, shape, rheological response and mechanical stability arise spontaneously from the interactions between elementary building blocks. In passive materials these are often reciprocal, energy conserving and subject to thermal fluctuations. I will discuss the physics of out-of-equilibrium solids and fluids built out of mechanically spinning components. These active materials which blur the line between solid and fluid, spontaneously exhibit phenomena from chiral surface waves, to perling instabilities, to dislocation motility and crystal-whorl states. These rich and lively dynamics enable inference of the rheological properties of these odd materials which include odd stress, odd viscosity and odd elasticity.