Design of a loop-gap resonator with bimodal uniform fields using finite element analysis

Libersky, Matthew; Silevitch, D. M.; Kouki, Ammar B.

doi:10.1109/compumag45669.2019.9032729

Cited by 3 publications

(7 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The requirements of high quality factor Q and field homogeneity on the one hand, and the physical size constraints imposed by the cryogenics and superconducting magnetic solenoid on the other, rule out the use of planar waveguide and cavity resonator structures. Instead, we adopt a loop-gap resonator (LGR) design [27,28] (Figs. 1(d,e)) that can be tuned over a wide range of frequencies while maintaining a high Q factor and an ac magnetic field highly concentrated on the sample volume.…”

Section: Methodsmentioning

confidence: 99%

“…GHz, the 4-loop 3-gap design illustrated in Fig. 1(d) allows the simultaneous probe of two resonant modes [28]; measurements between 900 MHz and 1.5 GHz used a 2-loop 1-gap design optimized for lower frequencies. Both designs can have their resonant frequencies tuned by approximately a factor of four by varying the gap capacitance via partial or complete filling with pieces of sapphire wafer, thereby increasing the dielectric constant.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Direct Observation of Collective Electronuclear Modes about a Quantum Critical Point

et al. 2021

View full text Add to dashboard Cite

Quantum phase transitions in spin systems are supposed to be accompanied by a soft collective mode, which has not been seen in experiments. Here, we directly measure the low energy excitation modes of a well-known realization of the Ising model in transverse field, LiHoF 4 , using microwave spectroscopy techniques to probe energies well below what is accessible via neutron scattering experiments. Instead of the single excitation expected for a simple quantum Ising system, we find and characterize a remarkable array of 'electronuclear' modes, arising from coupling of the spin-1/2Ising electronic spins to a bath of spin-7/2 Ho nuclear spins. The lowest-lying electronuclear mode softens at the approach to the quantum critical point from below and above, a softening that can be quenched with the application of a longitudinal magnetic field. The electronuclear mode structure has direct implications for the Ising systems that serve as the building blocks of adiabatic quantum computers and quantum annealers.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Direct Observation of Collective Electronuclear Modes about a Quantum Critical Point

et al. 2021

View full text Add to dashboard Cite

show abstract

“…In this work, we will treat the filling factor as a phenomenological parameter. The results of our theory are applied to experimental data on LiHoF 4 in a loop gap microwave resonator 33 .…”

Section: A Spin-photon Hamiltonianmentioning

confidence: 99%

“…As discussed following equation ( 16), the term linear in the photon operators is the instantaneous mean field Zeeman energy of the spins in the applied ac field, only now we are considering spins coupled to an effective photon position operator. The source of the diamagnetic term is the shift in the auxiliary field given in equation (33).…”

Section: Photon Hamiltonianmentioning

confidence: 99%

See 1 more Smart Citation

Theory of magnon-polaritons in quantum Ising materials

Mckenzie¹,

Libersky²,

Silevitch³

et al. 2022

Preprint

View full text Add to dashboard Cite

We present a theory of magnon-polaritons in quantum Ising materials, and develop a formalism describing the coupling between light and matter as an Ising system is tuned through its quantum critical point. The theory is applied to Ising materials having multilevel single-site Hamiltonians, in which multiple magnon modes are present, such as the insulating Ising magnet LiHoF4. We find that the magnon-photon coupling strengths may be tuned by the applied transverse field, with the coupling between the soft mode present in the quantum Ising material and a photonic resonator mode diverging at the quantum critical point of the material. A fixed system of spins will not exhibit the diamagnetic response expected when light is coupled to mobile spins or atoms. Without the diamagnetic response, one expects a divergent magnon-photon coupling strength to lead to a superradiant quantum phase transition. However, this neglects the effects of damping and decoherence present in any real system. We show that damping and decoherence may block the superradiant quantum phase transition, and lead to weak coupling between the soft magnon mode and the resonator mode. The results of the theory are applied to experimental data on the model system LiHoF4 in a microwave resonator.

show abstract

Cryogenic platform to investigate strong microwave cavity-spin coupling in correlated magnetic materials

Jones,

Mourigal,

Mounce

et al. 2024

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

We present a comprehensive exploration of loop-gap resonators (LGRs) for electron spin resonance (ESR) studies, enabling investigations into the hybridization of solid-state magnetic materials with microwave polariton modes. The experimental setup, implemented in a Physical Property Measurement System by Quantum Design, allows for measurements of ESR spectra at temperatures as low as 2 Kelvin. The versatility of continuous wave ESR spectroscopy is demonstrated through experiments on CuSO4·5H2O and MgCr2O4, showcasing the g-tensor and magnetic susceptibilities of these materials. The study delves into the challenges of fitting spectra under strong hybridization conditions and underscores the significance of proper calibration and stabilization. The detailed guide provided serves as a valuable resource for laboratories interested in exploring hybrid quantum systems through microwave resonators.

show abstract

Design of a loop-gap resonator with bimodal uniform fields using finite element analysis

Cited by 3 publications

References 9 publications

Direct Observation of Collective Electronuclear Modes about a Quantum Critical Point

Direct Observation of Collective Electronuclear Modes about a Quantum Critical Point

Theory of magnon-polaritons in quantum Ising materials

Cryogenic platform to investigate strong microwave cavity-spin coupling in correlated magnetic materials

Contact Info

Product

Resources

About