scholarly journals Perturbative quantum Monte Carlo study ofLiHoF4in a transverse magnetic field

2008 ◽  
Vol 78 (18) ◽  
Author(s):  
S. M. A. Tabei ◽  
M. J. P. Gingras ◽  
Y.-J. Kao ◽  
T. Yavors’kii
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Transverse Magnetic Field ◽  
Quantum Monte Carlo ◽  
Monte Carlo Study ◽  
Transverse Magnetic ◽  
Perturbative Quantum

MONTE CARLO STUDY OF ONE HOLE IN A QUANTUM ANTIFERROMAGNET

1992 ◽  
Vol 06 (05n06) ◽  
pp. 587-588
Author(s):  
S. Sorella
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Thermodynamic Limit ◽  
Quantum Monte Carlo ◽  
Finite Size ◽  
Monte Carlo Study ◽  
Mott Insulator ◽  
Trial Wavefunction ◽  
The One ◽  
Quantum Antiferromagnet

Using the standard Quantum Monte Carlo technique for the Hubbard model, I present here a numerical investigation of the hole propagation in a Quantum Antiferromagnet. The calculation is very well stabilized, using selected sized systems and special use of the trial wavefunction that satisfy the “close shell condition” in presence of an arbitrarily weak Zeeman magnetic field, vanishing in the thermodynamic limit. It will be shown in a forthcoming publication1 that the presence of this magnetic field does not affect thermodynamic properties for the half filled system. Then I have used the same selected sizes for the one hole ground state. I have investigated the question of vanishing or nonvanishing quasiparticle weight, in order to clarify whether the Mott insulator should behave just as conventional insulator with an upper and lower Hubbard band. By comparing the present finite size scaling with several techniques predicting a finite quasiparticle weight (see Fig.1) the data seem more consistent with a vanishing quasiparticle weight, i.e. , as recently suggested by P.W. Anderson2 the Hubbard-Mott insulator should be characterized by non-trivial excitations which cannot be interpreted in a simple quasi-particle picture. However it cannot be excluded , based only on numerical grounds, that a very small but non vanishing quasiparticle weight should survive in the thermodynamic limit.

scholarly journals Effect of small photon field on dose distribution in transverse magnetic field: A Monte Carlo study

2020 ◽  
Author(s):  
Jiaqi Fu ◽  
Cheng Ni ◽  
Yanfang Liu ◽  
Jingjie Zhou ◽  
Jie Fu
Keyword(s):  
Magnetic Field ◽  
Phase Space ◽  
Transverse Magnetic Field ◽  
Dose Distribution ◽  
Treatment Plan ◽  
Monte Carlo Study ◽  
Transverse Magnetic ◽  
Lung Water ◽  
Water Phantom ◽  
Photon Field

Abstract Background To investigate the effect of small photon field on dose distribution in transverse magnetic field by simulating the dose distribution on homogenous and heterogenous phantoms. Methods EGsnrc simulation was used to calculate the dose distribution of four phantoms irradiated by small photon field in transverse magnetic field B=0T , B=0.35T and B=1.5T . The photon beams were based on the phase space file of Varian Clinac_iX 6MV from the IAEA's online accelerator phase space database. The size of beams was 0.5cm×0.5cm , 1cm×1cm , 2cm×2cm and 4cm×4cm , respectively. Results In homogenous water phantom and 1.5T magnetic field, the distance of the dose build-up region decreased by 4mm compared with that without magnetic field. At the edge of the water phantom, the dose of central axis changed a 1.7% decrease in the field of 0.5cm×0.5cm to a 27% increase in the field of 4cm×4cm .The lateral profiles shifted by 1-3mm and the dose penumbra had asymmetry. In 0.35T magnetic field, the effect of magnetic field was insignificant. In water-air and water-lung phantom, the dose at the water-air and water-lung interface increased by 24.2%, 30.9%, respectively. However, at the air-water and lung-water interface, it decreased by 10.9% and 29.9% in the field of 2cm×2cm . In 0.35 T magnetic field, there was no significant change in the dose at the interface. In water-bone phantom, the dose at the water-bone interface increased. Conclusions In 1.5T magnetic field, when the field was small, the shift of lateral profile was obvious and the dose penumbra had asymmetry. At the interface of different tissue, the dose change depends on the size of the field, the strength of magnetic field and the change of tissue density. The effect of the magnetic field on the dose distribution needs to be considered during optimizing a treatment plan, to avoid dose hotspots at normal tissues.

scholarly journals Effect of small photon field on dose distribution in transverse magnetic field: A Monte Carlo study

2020 ◽  
Author(s):  
Jiaqi Fu ◽  
Cheng Ni ◽  
Yanfang Liu ◽  
Jingjie Zhou ◽  
Jie Fu
Keyword(s):  
Magnetic Field ◽  
Phase Space ◽  
Transverse Magnetic Field ◽  
Dose Distribution ◽  
Treatment Plan ◽  
Monte Carlo Study ◽  
Transverse Magnetic ◽  
Lung Water ◽  
Water Phantom ◽  
Photon Field

Abstract Background: To investigate the effect of small photon field on dose distribution in transverse magnetic field by simulating the dose distribution on homogenous and heterogenous phantoms.Methods: EGsnrc simulation was used to calculate the dose distribution of four phantoms irradiated by small photon field in transverse magnetic field B=0T, B=0.35T and B=1.5T. The photon beams were based on the phase space file of Varian Clinac_iX 6MV from the IAEA’s online accelerator phase space database. The size of beams was 0.5cm0.5cm, 1cm1cm, 2cm2cm and 4cm4cm, respectively. Results: In homogenous water phantom and 1.5T magnetic field, the distance of the dose build-up region decreased by 4mm compared with that without magnetic field. At the edge of the water phantom, the dose of central axis changed a 1.7% decrease in the field of 0.5cm0.5cm to a 27% increase in the field of 4cm4cm.The lateral profiles shifted by 1-3mm and the dose penumbra had asymmetry. In 0.35T magnetic field, the effect of magnetic field was insignificant.In water-air and water-lung phantom, the dose at the water-air and water-lung interface increased by 24.2%, 30.9%, respectively. However, at the air-water and lung-water interface, it decreased by 10.9% and 29.9% in the field of 2cm2cm. In 0.35 T magnetic field, there was no significant change in the dose at the interface. In water-bone phantom, the dose at the water-bone interface increased.Conclusions: In 1.5T magnetic field, when the field was small, the shift of lateral profile was obvious and the dose penumbra had asymmetry. At the interface of different tissue, the dose change depends on the size of the field, the strength of magnetic field and the change of tissue density. The effect of the magnetic field on the dose distribution needs to be considered during optimizing a treatment plan, to avoid dose hotspots at normal tissues.

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