In [1]:

import jaxquantum as jqt
import jax.numpy as jnp

import jaxquantum as jqt import jax.numpy as jnp

---------------------------------------------------------------------------
ModuleNotFoundError                       Traceback (most recent call last)
Cell In[1], line 1
----> 1 import jaxquantum as jqt
      2 import jax.numpy as jnp

ModuleNotFoundError: No module named 'jaxquantum'

Qarray¶

The Qarray is the fundamental building block of jaxquantum. It is heavily inspired by QuTiP's Qobj and built to be compatible with JAX patterns.

In [2]:

N = 50
state = jqt.basis(N, 0)
displaced_state = jqt.displace(N, 2.0) @ state
displaced_state.to_dm().header

N = 50 state = jqt.basis(N, 0) displaced_state = jqt.displace(N, 2.0) @ state displaced_state.to_dm().header

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[2], line 2
      1 N = 50
----> 2 state = jqt.basis(N, 0)
      3 displaced_state = jqt.displace(N, 2.0) @ state
      4 displaced_state.to_dm().header

NameError: name 'jqt' is not defined

In [3]:

pts = jnp.linspace(-4, 4, 100)
jqt.plot_wigner(displaced_state, pts)

pts = jnp.linspace(-4, 4, 100) jqt.plot_wigner(displaced_state, pts)

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[3], line 1
----> 1 pts = jnp.linspace(-4, 4, 100)
      2 jqt.plot_wigner(displaced_state, pts)

NameError: name 'jnp' is not defined

Batching¶

A crucial difference between a Qarray and Qobj is its bdim or batch dimension. This enables us to seamlessly use batching and numpy broadcasting in calculations using Qarray objects.

In [4]:

N = 50
state = jqt.basis(N, 0)
displaced_state = jqt.displace(N, jnp.array([[0.0, 0.5, 1.0],[1.5,2.0,2.5]])) @ state

displaced_state.header

N = 50 state = jqt.basis(N, 0) displaced_state = jqt.displace(N, jnp.array([[0.0, 0.5, 1.0],[1.5,2.0,2.5]])) @ state displaced_state.header

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[4], line 2
      1 N = 50
----> 2 state = jqt.basis(N, 0)
      3 displaced_state = jqt.displace(N, jnp.array([[0.0, 0.5, 1.0],[1.5,2.0,2.5]])) @ state
      5 displaced_state.header

NameError: name 'jqt' is not defined

In [5]:

pts = jnp.linspace(-4, 4, 100)
jqt.plot_wigner(displaced_state[0][0], pts)
jqt.plot_wigner(displaced_state[0][2], pts)
jqt.plot_wigner(displaced_state[1][1], pts)

pts = jnp.linspace(-4, 4, 100) jqt.plot_wigner(displaced_state[0][0], pts) jqt.plot_wigner(displaced_state[0][2], pts) jqt.plot_wigner(displaced_state[1][1], pts)

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[5], line 1
----> 1 pts = jnp.linspace(-4, 4, 100)
      2 jqt.plot_wigner(displaced_state[0][0], pts)
      3 jqt.plot_wigner(displaced_state[0][2], pts)

NameError: name 'jnp' is not defined

Constructing a batched Qarray manually¶

In [6]:

N = 50
a = jqt.displace(N, 0.0)
b = jqt.displace(N, 1.0)
c = jqt.displace(N, 2.0)
arr1 = jqt.Qarray.from_array([[a,b,c],[a,b,c]])
arr2 = jqt.displace(N, jnp.array([[0.0, 1.0, 2.0],[0.0, 1.0, 2.0]]))

jnp.max(jnp.abs(arr1[0][1].data-arr2[0][1].data))

N = 50 a = jqt.displace(N, 0.0) b = jqt.displace(N, 1.0) c = jqt.displace(N, 2.0) arr1 = jqt.Qarray.from_array([[a,b,c],[a,b,c]]) arr2 = jqt.displace(N, jnp.array([[0.0, 1.0, 2.0],[0.0, 1.0, 2.0]])) jnp.max(jnp.abs(arr1[0][1].data-arr2[0][1].data))

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
Cell In[6], line 2
      1 N = 50
----> 2 a = jqt.displace(N, 0.0)
      3 b = jqt.displace(N, 1.0)
      4 c = jqt.displace(N, 2.0)

NameError: name 'jqt' is not defined