Detection of Quantum Critical Points by a Probe Qubit
Abstract
Quantum phase transitions occur when the ground state of a quantum system undergoes a qualitative change when an external control parameter reaches a critical value. Here, we demonstrate a technique for studying quantum systems undergoing a phase transition by coupling the system to a probe qubit. It uses directly the increased sensibility of the quantum system to perturbations when it is close to a critical point. Using an NMR quantum simulator, we demonstrate this measurement technique for two different types of quantum phase transitions in an Ising spin chain.
- Publication:
-
Physical Review Letters
- Pub Date:
- March 2008
- DOI:
- 10.1103/PhysRevLett.100.100501
- arXiv:
- arXiv:0709.3273
- Bibcode:
- 2008PhRvL.100j0501Z
- Keywords:
-
- 75.10.Pq;
- 03.67.Lx;
- 64.60.-i;
- 73.43.Nq;
- Spin chain models;
- Quantum computation;
- General studies of phase transitions;
- Quantum phase transitions;
- Quantum Physics
- E-Print:
- A typo removed. Publication version