Phase Nodes

[appwagner]

Hi Steve, Is there a way get the phase at every node in a circuit consisting of JJs and inductors? I can get the phase difference across a junction, and I can infer the phase difference across an inductor by multiplying the branch current by the inductance and dividing by the flux quantum, but I was wondering if WRSPICE just kept track of that for you somewhere. Does ground have a predefined phase in this case like 0 mod 2pi ? I'm debugging some AQFP circuits and am trying to reconcile some energy minimization algebra with Kirchoff's current law so keeping track of phases explicitly is useful. Thanks as always for your help.

Cheers,

Andrew

[wrcad]

Hi Andrew,

In DC analysis with Josephson junctions, node “voltages” are actually phase, so node phase can be printed/plotted directly.

However, transient analysis is done in voltage mode, and the phase is not saved. The phase of a node can be computed explicitly, or inferred from junction and inductor phase differences.

The phase of ground can be taken as 0 modulo 2pi.

Regards, Steve

On May 4, 2022, at 11:51 AM, Andrew Wagner @.***> wrote:

Hi Steve, Is there a way get the phase at every node in a circuit consisting of JJs and inductors? I can get the phase difference across a junction, and I can infer the phase difference across an inductor by multiplying the branch current by the inductance and dividing by the flux quantum, but I was wondering if WRSPICE just kept track of that for you somewhere. Does ground have a predefined phase in this case like 0 mod 2pi ? I'm debugging some AQFP circuits and am trying to reconcile some energy minimization algebra with Kirchoff's current law so keeping track of phases explicitly is useful. Thanks as always for your help.

Cheers,

Andrew

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[appwagner]

Thanks Steve,

I think I got it figured out. The tricky part I was running into was remembering to account for the mutual inductance when a transformer is involved to properly calculate the phase as each vertex from the branch currents.

Cheers,

Andrew

On Oct 11, 2022, at 3:20 AM, Stephen Whiteley @.***> wrote:

Hi Andrew,

In DC analysis with Josephson junctions, node “voltages” are actually phase, so node phase can be printed/plotted directly.

However, transient analysis is done in voltage mode, and the phase is not saved. The phase of a node can be computed explicitly, or inferred from junction and inductor phase differences.

The phase of ground can be taken as 0 modulo 2pi.

Regards, Steve

On May 4, 2022, at 11:51 AM, Andrew Wagner @.***> wrote:

Hi Steve, Is there a way get the phase at every node in a circuit consisting of JJs and inductors? I can get the phase difference across a junction, and I can infer the phase difference across an inductor by multiplying the branch current by the inductance and dividing by the flux quantum, but I was wondering if WRSPICE just kept track of that for you somewhere. Does ground have a predefined phase in this case like 0 mod 2pi ? I'm debugging some AQFP circuits and am trying to reconcile some energy minimization algebra with Kirchoff's current law so keeping track of phases explicitly is useful. Thanks as always for your help.

Cheers,

Andrew

— Reply to this email directly, view it on GitHub https://github.com/wrcad/xictools/issues/13, or unsubscribe https://github.com/notifications/unsubscribe-auth/AEZ4PVD3K3GXMFFVCMF2DPLVILBK3ANCNFSM5VC3FVOQ. You are receiving this because you are subscribed to this thread.

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