MQC

Collaboration: Roma1

Laboratory: Roma-Univ. La Sapienza

National Responsible: G. Diambrini Palazzi (Rm1)

1. Goal of the experiment

The MQC experiment [the acronym stands for Macroscopic Quantum Coherence) aims to study the behavior of a ``macroscopic`` system to verify if the predictions given by the standard Quantum Mechanics Theory are still valid or if the Macrorealistic view should be used to describe its time evolution.

The experiment proposed by the Rome Group (G. Diambrini Palazzi and Carlo Cosmelli) has the goal of investigating the behavior of a two-state macroscopic system realized by means of a rf SQUID.

More on the experiment...

2.

Acrivities during 2001

The main experimental problem is the realization of a very low dissipative system, where the decoherence time is long enough to observe the rf SQUID`s Rabi oscillations.

A new integrated chip has been realized during this year and measurements at T=4.2 K have been performed.

Extensive studies have been done on the problem of isolating the system from any kind of external high frequency noise that, if not filtered, would destroy any quantum effect on the system.

The planned mlilestones have been fulfilled:

- Laser switch realization

- Integrated chip realization

- Measure at a temperature of 4.2K with integrated chip

Milestones 2002

Measurements of Macroscopic Quantum Coherence at a temperature of 10 mK | 30-06-2002

3. INFN contribution to the experiment in terms of manpower and financial support

- Manpower: 6 Researchers (3.6 FTE), 3 technicians (1 FTE)

- Budget for the Year 2002:13 kEuro.

4. Publications in refereed journals (Year 2001): 5

5. Conference talks (Year 2001):

6. Number of undergraduate thesis: 3

7. Leadership roles and primary responsibilities in the experiment:

- The national coordinator is G. Diambrini Palazzi from University of Rome, La Sapienza
- The Spokesperson is C. Cosmelli from University of Rome, La Sapienza.
- The Rome group plays a natural leading role within the collaboration for what concerns the final measurements and the data analysis on SQUID devices.

8. Innovative instruments

The MQC experiment has a particular technological significance:

- in developing very low dissipative quantum systems.
- in developing fast superconducting laser-driven trigger system.
- in realizing fully integrated superconducting systems working in the quantum regime.

9. Competing experiments

At present there is only the group of J. Lukens at Stony Brook (USA), trying to realize the same kind of measurements. The Lukens’s group at present is working on spectroscopic measurements, while we are planning time measurements.

The MQC group is the only group planning to realize (through hysteretic dc-SQUID readout) the non-invasive measurements necessary to the complete set of measurements.

10. International Committee which has reviewed the experiment.

The International Committee nominated by the Commissione Scientifica II, INFN, was formed by:

- J. Clarke (University of Berkeley, Berkeley, CA, USA)
- A. Barone (University of Naples Politecnico, Napoli, Italy)
- A. J. Leggett (University of Illinois at Urbana-Champaign, ILL, USA)
- G. C. Ghirardi (University of Trieste and SISSA, Trieste, Italy)