smc

Circles centered at $A$ and $B$ will overlap if $A$ and $B$ are closer to each other than if the circles were tangent. The circles are tangent when the distance between their centers is equal to the sum of their radii. Thus, the distance from $A$ to $B$ will be $2$. Since $A$ and $B$ are separated by $1$ vertically, they must be separated by $\sqrt{3}$ horizontally. Thus, if $|A_x-B_x|<\sqrt{3}$, the circles intersect. Now, plot the two random variables $A_x$ and $B_x$ on the coordinate plane. Each variable ranges from $0$ to $2$. The circles intersect if the variables are within $\sqrt{3}$ of each other. Thus, the area in which the circles don't intersect is equal to the total area of two small triangles on opposite corners, each of area $\frac{(2-\sqrt{3}{)}^2}{2}$. So, the total area of the 2 triangles sums to $(2-\sqrt{3}{)}^2$. Since the total $2\times 2$ square has an area of $4$, the probability of the circles not intersecting is $\frac{(2-\sqrt{3}{)}^2}{4}$. But remember, we want the probability that they do intersect. We conclude the probability the circles intersect is:$$1-\frac{(2-\sqrt{3}{)}^2}{4}=\boxed{\frac{4\sqrt{3}-3}{4}}.$$