# Dr Lluis Masanes

**Senior Research Fellow**

### Dept of Physics & Astronomy

### Faculty of Maths & Physical Sciences

- Joined UCL
- 6th Jan 2014

## Research summary

My research is on quantum information science and its connections to other fields like the foundations of quantum mechanics, information theory, complexity theory, quantum field theory, quantum thermodynamics and quantum gravity. I have extensively contributed to the areas of quantum cryptography, entanglement theory, Bell inequalities, reconstructions of quantum theory and nano-scale thermodynamics. The following is a selection of my most relevant scientific contributions.

**All entangled states constitute useful resources**for information processing tasks like teleportation, Bell-inequality violation and pure entanglement distillation. This result brought a sharp answer to the contemporary question "what is bound entanglement useful for?", and it has been extended to different setups by several authors.**Reconstruction of quantum theory from physical principles**having a simple and direct meaning (Nature Physics highlight, July 2011). This contrasts with the standard formulation in terms of abstract postulates with no clear meaning.**Proof of the area law in arbitrary spatial dimensions.**First general proof that the entropy of a region of a lattice system in its ground state is proportional to the boundary area of the region (instead of the volume), provided that the system has local interactions and a moderate density of low-energy levels.**Device-independent quantum key distribution.**Discovery that certain protocols for key distribution based on the violation of Bell inequalities enjoy a higher level of security than the standard quantum key distribution protocols. I also provided the first security proof for an efficient device-independent quantum key distribution protocol.**Derivation of the Third Law of Thermodynamics.**This is a model-independent lower bound on the resources that are necessary for bringing a system to any temperature. In particular, it shows the impossibility to reach absolute zero. This also puts limits how fast information can be erased.**The quantum Chernoff bound**is the quantum generalisation of a very important result in probability theory. It quantifies the statistical distinguishability between any pair of quantum states.