2015 Fiscal Year Research-status Report
| Project/Area Number |
26400340
|
|---|
| Research Institution | Okinawa Institute of Science and Technology Graduate University |
|---|
Principal Investigator |
コンスタンチノフ デニス 沖縄科学技術大学院大学, Quantum Dynamics Unit, 准教授 (50462685)
|
|---|
| Project Period (FY) |
2014-04-01 – 2017-03-31
|
| Keywords | strong coupling / nucelamagnetci resonance / quantum memory |
|---|
| Outline of Annual Research Achievements |
During FY2015, we continued our experimental investigation of the nuclear spin resonance in weakly-ferromagnetic MnCO3 crystalline sample. These investigations have progressed in two main direction:
1. Strong coupling of nuclear spin ensemble in MnCO3 to a microwave resonator mode. In the first experiment, we have observed the avoided crossing in the split-ring resonator transmission spectrum. This corresponds to the normal-mode splitting in the coupled nuclear-electromagnetic mode. The obtained cooperativity factor of C=0.2 indicated nearly-strong coupling regime in this coupled system. This result was published in the Physical Review Letters.
In subsequent experiment, we managed to fabricate a new resonator with 30-times larger quality factor, thus reaching the cooperativity number of C=6 >>1,thus clearly demonstrating the achievement of the strong coupling regime.
2. In accordance with our proposal to use magnetic materials with strong hyperfine interaction (MnCO3 and other similar systems) for quantum memory devices, we have investigated the T2 time for nuclear spins using the spin-echo technique. Preliminary, we find T2 time of several tens of microseconds, significantly longer than in electron-spin ensembles also proposed for quantum memory applications. We also find very strong temperature dependence of T2 time and hope to obtain very long T2 time (>100 musec) below 100 mK.
|
| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
The research progressed very well. Unexpectedly, we observed the phenomenon of the strong coupling of nuclear spin ensemble in MnCO3 to microwave electro-magnetic mode. To the best of my knowledge, this is the first observation of such coupling for nuclear spins, and it promises possibility to use such systems for quantum memory applications.
In addition, our spin-echo experiments in MnCO3 show rather long T2 time, which confirms usefulness of such systems for long-live quantum memory.
|
| Strategy for Future Research Activity |
In FY2016, we plan to continue to investigate this material (and other similar crystalline systems) for quantum memory applications.
1. We plan to finish our spin-echo studies and find T2 time for nuclear spins in large range of temperatures down to 10 mK.
2. We plan to improve on the quality factor of resonators in order to increase the cooperativity factor further.
3. We plan to investigate the possibility of Bose-Einstein Condensation of nuclear magnons (our original goal) and, if successful,invetsigate string coupling of condensate to an electromagentic mode in microwave resonator.
4. We also plan to investigate double electron-nuclear magnetic resonance as an additional tool for characterization of the nuclear system.
|
| Causes of Carryover |
Round off error in estimating the expected expenditure in FY2015.
|
| Expenditure Plan for Carryover Budget |
Will purchase consumables.
|
