The Stability Limit and other Open Questions on Water at Negative Pressure

Liquid water exhibits numerous anomalies, such as its expansion upon cooling below 4◦C. One of the explanations put forward involves polymorphism: two different liquid phases could exist at low temperature, in the supercooled region; this proposal has focused significant experimental and theoretical interest on the supercooled regime. We study another metastable state of water, where the liquid is at negative pressure, as explained in Section 1.2. The properties of water in this region of the phase diagram are largely unknown, although they could shed light on the debate about supercooled water, as argued in Section 1.3. Recent experiments have questioned the exact value of the limit of metastability of water at negative pressure. In Section 1.4, we present some techniques used to explore this exotic state. In Section 1.5 we discuss studies of the stability limit of water under tension based on these techniques. In Section 1.6, we consider other properties of water in this regime. Finally, we