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Related Experiment Video

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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses

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Simple empirical order parameter for a first-order quantum phase transition in atomic nuclei.

Dennis Bonatsos¹, E A McCutchan, R F Casten

¹Institute of Nuclear Physics, National Center for Scientific Research Demokritos, GR-15310 Aghia Paraskevi, Attiki, Greece.

Physical Review Letters

|June 4, 2008

Summary

A new order parameter, the ratio of 6+ to 0+ state energies, effectively distinguishes nuclear phase transitions. This ratio shows unique behavior in the critical region, indicating potential underlying symmetries.

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Area of Science:

Nuclear physics
Atomic nuclei structure
Quantum mechanics

Background:

Phase transitions in atomic nuclei are crucial for understanding nuclear structure.
Distinguishing between first- and second-order phase transitions is essential.
Existing order parameters may lack simplicity or ease of measurement.

Purpose of the Study:

To introduce a simple, empirical, and easily measurable order parameter for first-order phase transitions in atomic nuclei.
To differentiate between first- and second-order nuclear phase transitions.
To investigate the behavior of this parameter in the critical region.

Main Methods:

Calculating the ratio of the energies of the first excited 6+ and 0+ states.
Analyzing data from Nd-Dy isotopes.
Utilizing the interacting boson approximation (IBA) model in the large N_B limit.

Main Results:

The proposed ratio of 6+ to 0+ state energies serves as an effective order parameter.
This parameter distinguishes between first- and second-order transitions.
A special value of this ratio is observed in the critical region for Nd-Dy data.
The interacting boson approximation model reveals repeating degeneracies between alternate yrast and successive 0+ states near first-order phase transitions.

Conclusions:

The 6+/0+ energy ratio is a viable order parameter for nuclear phase transitions.
The observed degeneracies in the critical region suggest a possible underlying symmetry in atomic nuclei.
This finding aids in the characterization and understanding of nuclear structure and dynamics.