Dear All,
We are trying to reproduce results from this paper using the dirloop_sse code.
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.89.047202
Typically we setup the simulation such that it calculates the spin-spin correlations and then calculate the staggered susceptibility from that. The results for uniform susceptibility obtained that way seem to reproduce well the known results, however it is not the case of the staggered susceptibility. In particular the staggered susceptibility seems to be the same for even and odd chain lengths and to scale in a bizarre way with length. This happens even for very short chains where we would expect the difference between odd/even to be significant.
Is this a known problem with a simple explanation?
Regards, Stanislaw and Kirill
Dear Kirill,
Integration of the staggered correlation function, multiplied by the inverse temperature, does not yield the staggered susceptibility, as the staggered magnetization does not commute with the Hamiltonian.
You have to integrate the (staggered) response function, instead.
Best regards, Synge
2018/09/06 21:44、Stanislaw Galeski galeskis@phys.ethz.chのメール:
Dear All,
We are trying to reproduce results from this paper using the dirloop_sse code.
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.89.047202
Typically we setup the simulation such that it calculates the spin-spin correlations and then calculate the staggered susceptibility from that. The results for uniform susceptibility obtained that way seem to reproduce well the known results, however it is not the case of the staggered susceptibility. In particular the staggered susceptibility seems to be the same for even and odd chain lengths and to scale in a bizarre way with length. This happens even for very short chains where we would expect the difference between odd/even to be significant.
Is this a known problem with a simple explanation?
Regards, Stanislaw and Kirill
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Dear Synge,
thank you very much for the answer. We have figured out today from Snadviks paper that we indeed need to calculate something else... However we still have a question how does one extract (calculate) the response function using alps and the dirloop_sse?
Sorry if the questions seem naive, we are experimentalists and real newbies to QMC calculations.
Best, Stanislaw
On 07.09.2018 13:32, Synge Todo wrote:
Dear Kirill,
Integration of the staggered correlation function, multiplied by the inverse temperature, does not yield the staggered susceptibility, as the staggered magnetization does not commute with the Hamiltonian.
You have to integrate the (staggered) response function, instead.
Best regards, Synge
2018/09/06 21:44、Stanislaw Galeski galeskis@phys.ethz.chのメール:
Dear All,
We are trying to reproduce results from this paper using the dirloop_sse code.
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.89.047202
Typically we setup the simulation such that it calculates the spin-spin correlations and then calculate the staggered susceptibility from that. The results for uniform susceptibility obtained that way seem to reproduce well the known results, however it is not the case of the staggered susceptibility. In particular the staggered susceptibility seems to be the same for even and odd chain lengths and to scale in a bizarre way with length. This happens even for very short chains where we would expect the difference between odd/even to be significant.
Is this a known problem with a simple explanation?
Regards, Stanislaw and Kirill
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Indeed, the dirloop_sse program should output "Staggered Susceptibility". If not, you can use "loop".
Best, Synge
2018/09/07 21:07、Stanislaw Galeski galeskis@phys.ethz.chのメール:
Dear Synge,
thank you very much for the answer. We have figured out today from Snadviks paper that we indeed need to calculate something else... However we still have a question how does one extract (calculate) the response function using alps and the dirloop_sse?
Sorry if the questions seem naive, we are experimentalists and real newbies to QMC calculations.
Best, Stanislaw
On 07.09.2018 13:32, Synge Todo wrote: Dear Kirill, Integration of the staggered correlation function, multiplied by the inverse temperature, does not yield the staggered susceptibility, as the staggered magnetization does not commute with the Hamiltonian. You have to integrate the (staggered) response function, instead. Best regards, Synge 2018/09/06 21:44、Stanislaw Galeski galeskis@phys.ethz.chのメール:
Dear All, We are trying to reproduce results from this paper using the dirloop_sse code. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.89.047202 Typically we setup the simulation such that it calculates the spin-spin correlations and then calculate the staggered susceptibility from that. The results for uniform susceptibility obtained that way seem to reproduce well the known results, however it is not the case of the staggered susceptibility. In particular the staggered susceptibility seems to be the same for even and odd chain lengths and to scale in a bizarre way with length. This happens even for very short chains where we would expect the difference between odd/even to be significant. Is this a known problem with a simple explanation? Regards, Stanislaw and Kirill
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Unfortunately it does only output staggered magnetization. However ultimately what we would like to calculate is the transverse staggered susceptibility in a magnetic field in a spin ladder. So far we thought we can use the 'Greens function' for that purpose. Now i understand it is not the case and we would need to calculate the transverse response function?
In fact the results have been very promising so far (using the green function), can it be that for an even number of spins (and even number of rungs) the staggered transverse susceptibility calculated using the 'greens function' would produce the correct result?
If not is there a reasonably easy way of modifying the code to get the correct observable?
Best, Stanislaw
On 07.09.2018 14:43, Synge Todo wrote:
Indeed, the dirloop_sse program should output "Staggered Susceptibility". If not, you can use "loop".
Best, Synge
2018/09/07 21:07、Stanislaw Galeski galeskis@phys.ethz.chのメール:
Dear Synge,
thank you very much for the answer. We have figured out today from Snadviks paper that we indeed need to calculate something else... However we still have a question how does one extract (calculate) the response function using alps and the dirloop_sse?
Sorry if the questions seem naive, we are experimentalists and real newbies to QMC calculations.
Best, Stanislaw
On 07.09.2018 13:32, Synge Todo wrote: Dear Kirill, Integration of the staggered correlation function, multiplied by the inverse temperature, does not yield the staggered susceptibility, as the staggered magnetization does not commute with the Hamiltonian. You have to integrate the (staggered) response function, instead. Best regards, Synge 2018/09/06 21:44、Stanislaw Galeski galeskis@phys.ethz.chのメール:
Dear All, We are trying to reproduce results from this paper using the dirloop_sse code. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.89.047202 Typically we setup the simulation such that it calculates the spin-spin correlations and then calculate the staggered susceptibility from that. The results for uniform susceptibility obtained that way seem to reproduce well the known results, however it is not the case of the staggered susceptibility. In particular the staggered susceptibility seems to be the same for even and odd chain lengths and to scale in a bizarre way with length. This happens even for very short chains where we would expect the difference between odd/even to be significant. Is this a known problem with a simple explanation? Regards, Stanislaw and Kirill
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