Philip Stamp

Research Interests

(A) STRONGLY-CORRELATED CONDENSED MATTER SYSTEMS

These are systems in which interactions (eg., between electrons) play a key role, and can in fact change the physics in fundamental ways.

A1. SUPERFLUIDITY and SUPERCONDUCTIVITY: Two key problems in this field concern the nature of the 'normal' state underlying superconductivity in high-Tc superconductors (is it a Fermi Liquid, or some more peculiar state?), and the physics of the quantum vortices that exist in the superfluid state.

A2. QUANTUM MAGNETISM: The main question of current interest in this field concerns the new kinds of order that can exist in magnetic systems where interactions can frustrate classical ordering; and the quantum dynamics of these systems. This field strongly overlaps with 'quantum nanomagnetism', the field concerned with spin qubits, tunneling spins, etc. (see A3. below)

A3. QUANTUM SPIN NETS and SPIN QUBITS: One of the most exciting challenges in physics is to devise networks of 'qubits' (ie., quantum 2-level systems) which can behave as a quantum information processing system. In our view the most promising candidates for the qubits are electronic and/or nuclear spins, provided the fundamental problem of decoherence can be brought under control. 

A4. QUANTUM COHERENCE PHENOMENA IN BIOLOGY: In the last few years experiments have shown that some key biological processes rely on room-temperature quantum coherence. Key examples are photosynthesis, and the use of 'magnetoreception molecules' for navigation by birds and some mammals. 

A5. QUANTUM GLASSES: The main problem here (described by both PW Anderson and AJ Leggett as a really central problem in physics) is to understand the dynamics of a set of localised modes (defects) in a disordered solid, coupled by strain fields, electric dipole interactions, phonons, etc. A key mystery is the existence of low-T 'universality' in this dynamics.

A6. GRAPHENE: The discovery of graphene in 2004, the demonstration that its 'Dirac electron' properties were those predicted by Semenoff in 1984 using topological field theory, and the promise of a new generation of graphene-based electronic devices, has led to an explosion of activity.

B. DECOHERENCE, QUANTUM INFORMATION, and GRAVITY

Some of the condensed matter questions described above lead to much more general problems in physics. A key question is to understand decoherence in Nature, and also in quantum information processing We are dealing here not just with conventional environmental decoherence, caused by coupling to spin and oscillator bath modes, but also other possible 'intrinsic decoherence' mechanisms. One such mechanism is suggested by the clash between Quantum Mechanics and General Relativity, the 2 foundational pillars of 20th century physics; this mechanism is sometimes called 'gravitational decoherence'. We are thus led to the most important unsolved problem in physics, viz., how to go beyond these 2 central theories, to find a new theory embracing both.

B1. MECHANISMS of ENVIRONMENTAL DECOHERENCE

B2. DECOHERENCE and QUANTUM COMPUTING

B3. GRAVITATIONAL DECOHERENCE and QUANTUM GRAVITY