Computing and the Future 10 - A Warm Quantum Computer

This is a preposterous title, and I am no expert in any of this, but I had an idea about this topic that is so seductive I would be remiss in not writing it down. Here it is in brief:

Let’s say that we can simulate all the properties of a qubit with a gyroscope. The gyro is be mounted in a traditional gimbal that has two degrees of freedom, that allow the gyro to take on any possible value in two angles. We describe the orientation of the gyro in spherical coordinates of unit radius, theta and phi, which can transformed with no loss of generality to the more familiar  coordinates of latitude and longitude so for convenience I will use those; A qubit has two degrees of freedom. The following video explains this analogy.

A gyroscope has spin, and if we put a unit poynting-vector at the center of the qubit, we can denote the state of the qubit by the latitude and longitude of its spin vector. For now, and possibly forever we will assume that the spin rate is constant and non-zero. If the spin vector has a negative value, we assume that the spin is in the other direction.

We need to acknowledge a second property of qubits, and that is, they have the ability to be entangled. We would like to create a model such that if we choose, two (or more) gyros can become entangled. For the time being, and possibly forever we will assume that if one gyro has spin V, that the other gyro has spin -V, and further, that whatever happens to gyro1, also happens to gyro2 in complement according to the rules of entanglement.

Now we do not live in the age of levers, pulleys and springs per se. Consider for a moment a hypothetical electronic circuit that was, in all its momentum and spin glory able to simulate the aspects of a gyroscope. This circuit would have a stable signal that would somehow appropriately and fully represent the spin of the gyro. In other words, we replace the mechanical gyro with an equivalent circuit, or possibly a MEMS device. Below is a functioning equivalent gyroscope circuit modeled by this author using a schematic published in this research gate paper and the J. Falstad online circuit simulator:

Gyroscope Equivalent Circuit

Here is an actual MEMS gyroscope that retails for $15.80 USD on Amazon.

The advantage of the equivalent circuit is that there are no moving parts. If the MEMS circuit were used, power would have to be routed to the board along with input and output connections. Additionally it would have to be gimbaled, which would add to its expense and complexity. Its response would be inhibited by aerodynamic drag on the board assembly, which could necessitate its confinement to a vacuum tube envelope. It could be combined with a wireless communication system to simplify the mechanical pinouts, but I still would prefer the equivalent circuit.

Now I propose, and this is the seductive part, that the entanglement of a qubit manifested as an equivalent gyro circuit and its doppelganger can be accomplished via an RF mixer such as that which occurs in a Software Defined Radio. Once could choose a basic frequency mixer, or the famous IQ mixer that reproduces the full complexity of the Hilbert Space of the qubit with both the real and complex components of the signal. The latter would require a local oscillator acting as a clock.

The I and Q signals could represent the latitude and longitude coordinates of the entangled qubits. Entanglement would place constraints of complementarity on the two gyros.

An RF mixer has the property that it does not sum its inputs like an audio mixer, but rather multiplies them producing an output that is, paradoxically, the sum and difference of the input signals.

After the system was configured with a given problem, which would mean initializing the equivalent circuits and placing the appropriate qubits in superposition, the system would  reach some kind of equilibrium after a settling time. At that time its state could be measured. At the moment of measurement the wave functions collapse into an actual real result per the commonly referenced Schrodinger's suitcase, the cat would be dead or alive.

When a 400 nm ultraviolet parent photon is sent through a lithium niobate crystal, it can be split into two entangled 800 nm photons named Alice and Bob per the Nicolas Gisin experiment, which is informally, but very readably documented, in this New York Times article. The frequency of Alice and Bob must be exactly half that of their parent due to conservation of energy. Alice and Bob are entangled meaning that if Alice has a spin of up, then Bob has a spin of down. Alice's vector could be oriented in any latitude and longitude direction, Bob's would simply point the other way.

Now I mention the lithium niobate example for the very specific reason that optical photons can be split using the nanoscopic lattice of the lithium crystal. If we are willing to work with longer photon wavelengths in the radio frequency spectrum then we could split Gigahertz photons with a grid whose centers were on the order of a centimeter apart. They could be miniatured later of course, once things were completely characterized and understood. There is a serious cost advantage to not thinking too small when prototyping, especially in the RF domain being proposed here.

One thing that Quantum Computing (QC) has lacked, is the "killer app" that would launch it into everyday use. Most applications of QC have to do with encryption and decryption. Cracking codes is certainly interesting but I believe QC may have more popular "killer" utility applications in medical imagery, remote sensing, temporal imaging and generalized image processing.  Imagine being able to produce an image from a great distance in extremely short time frames, possibly including those simultaneously with the occurrence of the event.

The photon splitting, via antenna, or crystal needs a complimentary photon combining operator for mathematical completeness. In Radio Frequency parlance this is "up conversion" versus the "down conversion" performed by the lithium niobate crystal. Each function should have its inverse for full architectural utility. On January 17, 2019 I ran across an article in Phys.org that promises exactly this:

In summary, if it is, or can be made the case that these statements are true for some electronic system, miniature or not, then it should be possible to simulate a quantum computer at room temperature with such a system.