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Theory of smeared quantum phase transitions
1Department of Physics, Duke University, Durham, North Carolina 27708, USA.
Physical Review Letters
|July 23, 2008
Summary
We developed a theory for quantum phase transitions in disordered systems with dissipation. Ohmic dissipation smears the quantum critical point, altering low-temperature properties and the phase diagram.
Area of Science:
- Condensed Matter Physics
- Quantum Many-Body Systems
- Disordered Systems
Background:
- Quantum phase transitions (QPTs) are fundamental to understanding many-body quantum systems.
- Disorder and dissipation are crucial factors that can significantly alter QPTs.
- The random transverse-field Ising model is a key platform for studying QPTs.
Purpose of the Study:
- To develop an analytical theory for QPTs in dissipative random transverse-field Ising chains.
- To investigate the effects of Ohmic dissipation on the quantum critical point.
- To determine the low-temperature properties and phase diagram of the system.
Main Methods:
- Analytical strong-disorder renormalization group theory.
- Solving renormalization flow equations for Ohmic dissipation.
- Asymptotic analysis of low-temperature properties.
Main Results:
- The interplay of quantum fluctuations and Ohmic dissipation destroys the quantum critical point by smearing.
- Asymptotically exact results for low-temperature properties were obtained.
- The phase diagram and behavior of observables near the smeared transition were determined.
Conclusions:
- Ohmic dissipation fundamentally alters the nature of quantum criticality in disordered systems.
- The developed theory provides a framework for understanding smeared quantum phase transitions.
- The findings offer insights into the low-temperature behavior of dissipative quantum models.
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