Chapter 569

After the general scheme of the experiment was finalized, the next step was to be busy with the research.

Since there are only two people in the research group, Academician Guo and Gu Lu, everything needs to be done in person.

From the calculation of one or two values to the construction of the overall framework, Gu Lu and Academician Guo need to do it in person.

Simply, those tedious little jobs won't take too much effort on the part of the two of them.

On the contrary, the main research content of the experiment will take a lot of time for two people.

It took two days for Gu Lu and Academician Guo to build the detailed framework of the 25-qubit semiconductor chip.

This was followed by a step-by-step experimental plan according to the framework of the protocol.

…………

In this hectic state, time flies.

In the blink of an eye, half a month passed.

It's the end of October.

The weather gradually became colder, Gu Lu sat in front of an experimental instrument in long sleeves, and substituted the experimental data displayed on the screen into the formula that had been reasoned a long time ago.

Smack!

Gu Lu snapped his fingers.

"Perfect!"

Looking at the derivative conclusions drawn on the scratch paper, Gu Lu's face was filled with a smile of joy.

This result is exactly what Gu Law Firm wants.

No, no, no!

It is even said that the result is much more perfect than Gu Lu expected.

"Next, it's time to draw a simplified structure diagram of the quantum entanglement system!"

Moving his fingers, Gu Lu turned the pen in his hand into a pen flower on his fingertips.

"Let's get started!"

Half an hour later......

It took ten pages of A4 paper for Gu Lu to draw a schematic diagram of the structure of the quantum entanglement system.

After aligning the ten pages of A4 paper and nailing them up with a stapler, Gu Lu got up and came to Academician Guo, who was sitting in the other corner of the laboratory.

"Old Guo, I've already done the structural sketch, you can take a look. ”

Gu Lu handed the bound simplified structure diagram of the quantum entanglement system to Academician Guo.

"Wow, so fast!" Academician Guo was surprised at first, and then put on his reading glasses and began to look through the pages.

Although Gu Lu's painting skills are not good, because the theoretical tone of this quantum entanglement system was set by Academician Guo and Gu Lu together, even if Gu Lu's painting skills are a bit simple, Academician Guo can still understand it at a glance.

The 25-bit qubit entanglement system discussed by Gu Lu and Academician Guo is based on the eight-photon system, and uses the three degrees of freedom of each photon: path, polarization, and orbital angular momentum, to expand into 25-bit qubits.

This method is also known as "hyperquantum entanglement".

The way Gu Lu and Academician Guo adopted is very different from the traditional way.

Traditionally, the number of qubits has been increased by increasing the number of photons or ions.

For example, a 25-bit quantum entanglement system is based on a system containing 25 photons.

However, Gu Lu adopts this method, which uses multiple degrees of freedom to increase the number of extended qubits more efficiently.

Compared with the traditional method, the method conceived by Gu Lu and Academician Guo has many advantages.

For example, it is possible to use a smaller number of particles (photons) at the same qubit, further increasing the stability of the entire system.

Or some quantum information technologies that require a lot of computation and storage will also benefit, such as quantum ultra-dense coding, simplified quantum logic gate technology, and multi-degree-of-freedom single-photon transmission technology.

Of course......

Gu Lu and Academician Guo's new way of using multi-particle and multi-degrees of freedom to increase the number of qubits has not been realized before.

In theory, this approach is quite possible.

But whether it is actually possible or not still needs to wait for the final experimental results.

In addition to some advantages of the new plan, the most important reason why the two abandoned the traditional way and adopted this risky plan is time.

If this scheme is adopted, the time will be much shorter, so Gu Lu and Academician Guo have decided in this way.

…………

And Gu Lu is here.

While Academician Guo looked at the schematic diagram, Gu Lu was explaining on the side.

“…… Here, A and B are the encoded parts of the quantum entanglement, and CDE is the corresponding measurement part. ”

"Look at the fourth page, at this entrance, an ultrafast laser with a wavelength of 788nm, a pulse duration of 120fs, and a repetition rate of 76MHz is converted to light at 394nm through a dichroic filter of lithium triborate. ”

The light then proceeds to produce three pairs of entangled photons, as illustrated in this diagram, by forming a sandwich-like nonlinear crystal consisting of two β-barium borate and a half-wave plate. ”

"Then, each photon is modified in space and phase by YVO4 crystals of different thicknesses and orientations, and then through PBS encoding polarization, PBS encoding pathway, and SPP encoding orbital angular momentum, the final result is a single-photon quantum state with three degrees of freedom......"

Gu Lu explained endlessly.

Academician Guo listened very carefully and asked one or two questions from time to time.

Finally, Gu Lu pointed to the last picture and said, "In my calculations, the 25-bit qubit quantum entanglement system uses a total of 48 single-photon detectors, which can measure 33554432 combinations at the same time, and the final quantum state fidelity has reached 0.708±0.016!"

"Good job!" Academician Guo closed the structural sketch in his hand, and raised his head and looked down on Gu Lu with satisfaction, "The result we want is what you depict in this structural diagram." ”

A smile rose on the corner of Gu Lu's mouth, "Yes, Guo Lao, next, we just need to turn on the firepower and start the experimental measurement data part by part." ”

Academician Guo nodded, "That's right, first of all, the first link, the first two parts, that is, the coding part of quantum entanglement, have been tested with various parameters!"

"I'm in charge of the first part, Professor Gu, and you're in charge of the second part. ”

"Yes!" Gu Lu ordered.

…………

The days passed.

Gu Lu lives a life of two points and one line in the laboratory and the apartment.

After Gu Lu built the basic framework and drew a simple structure diagram of the quantum entanglement system, the subsequent research work became a bit boring.

The main reason why physics topics take a lot more time than mathematics topics is that physics topics require experiments, and a large number of experiments are carried out.

And the time of each experiment is not so short.

A few simple experiments can produce results in a matter of seconds.

For some complex experiments, it will take a day or two for the data to come out.

And there is no guarantee that every experiment will be successful.

In this part of the time, Gu Lu spent a lot of time waiting for the results of the experiment.

However, on the whole, the progress of the experiment was still satisfactory to Gu Lu.

And just like that, the time entered December.