# Re: [Kwant] Units of the wavefunction and velocity

```Hi Prof. Akhmerov,

Sorry I made a mistake in the units of 'I'. Isn't 'I' here the probability
current and not the charge current? We would just have to multiply 'I' by e
to get the charge current, right?```
```
Thanks,

On Mon, Jan 23, 2017 at 9:53 AM, Anton Akhmerov <anton.akhmerov...@gmail.com
> wrote:

>
> I might be missing some factors here, but the unit of current is
> elementary charge / unit of time. The unit of time is hbar / unit of energy
> that you used in defining your tight-binding model.
>
> Best,
> Anton
>
> On Mon, Jan 23, 2017 at 3:49 PM, Harshad Sahasrabudhe <hsaha...@purdue.edu
> > wrote:
>
>> Hi,
>>
>> I was wondering what units would the wavefunction obtained from Kwant
>> have?  I was thinking they would have the units 1/sqrt(nm.eV) (since my
>> energies are in eV and lengths are in nm) as the modes are normalized
>> according to
>>
>> [image: Inline image 1]
>>
>> How would I calculate the velocity of the mode, if the modes are
>> normalized to carry unit current?
>>
>> Thanks,