1. An apparatus comprising:
a register configured to store a coded entangled qubit state generated using a quantum stabilizer code;
a measurement circuit configured to perform a redundant measurement of a set of syndrome values corresponding to the coded entangled qubit state, wherein the redundant measurement is performed based on a low-density parity-check (LDPC) error-correction code; and
a decoder configured to apply the LDPC error-correction code to correct a measurement error in the set of syndrome values.
2. The apparatus of claim 1, wherein the LDPC error-correction code is a low-density generator-matrix code.
3. The apparatus of claim 1, wherein the LDPC error-correction code has a sparse parity-bit generator sub-matrix.
4. The apparatus of claim 3, wherein the parity-bit generator sub-matrix has a density that is smaller than about 10%.
5. The apparatus of claim 3, wherein the parity-bit generator sub-matrix has a density that is between about 5% and about 25%.
6. The apparatus of claim 1, wherein all rows in a transposed parity-bit generator sub-matrix of the LDPC error-correction code have a same constant weight.
7. The apparatus of claim 6, wherein the transposed parity-bit generator sub-matrix has a column-weight distribution that causes EXIT functions corresponding to variable and check nodes of a bipartite graph of the LDPC error-correction code not to intersect.
8. The apparatus of claim 1, further comprising a state-recovery circuit configured to correct an error in the coded entangled qubit state based on a syndrome value received from the decoder.
9. The apparatus of claim 8, wherein the state-recovery circuit is further configured to:
determine, based on a corrected set of syndrome values, an error operator corresponding to a probable error in the coded entangled qubit state; and
process the coded entangled qubit state based on the error operator in a manner that corrects the probable error therein.
10. The apparatus of claim 8, further comprising an array for storing a plurality of coded entangled qubit states, wherein the apparatus is configured to:
transfer a selected coded entangled qubit state from the array to the register; and
transfer the selected coded entangled qubit state from the register to the array in response to modifying the selected entangled qubit state based on the error operator.
11. The apparatus of claim 1, wherein the measurement circuit comprises:
a first set of measurement modules coupled to the register, wherein each measurement module is configured to measure a respective syndrome value of the coded entangled qubit state based on a respective one of first binary vectors;
a second set of measurement modules coupled to the register, wherein each measurement module is configured to measure a respective parity value of the coded entangled qubit state based on a respective one of second binary vectors, wherein each parity value is related to some of the syndrome values as defined by the LDPC error-correction code.
12. The apparatus of claim 11, wherein:
the measurement module in the first set comprises a respective soft-output detector configured to generate the respective syndrome value as a log-likelihood-ratio (LLR) value; and
the measurement module in the second set comprises a respective soft-output detector configured to generate the respective parity value as an LLR value.
13. The apparatus of claim 12, wherein the decoder is configured to correct the measurement error by executing a message-passing decoding algorithm corresponding to the LDPC error-correction code.
14. The apparatus of claim 13, wherein said message-passing decoding algorithm is initialized using the LLR values generated by the measurement modules.
15. The apparatus of claim 11, wherein a measurement module in the measurement circuit comprises:
a sequence of quantum gates connected to the register and configured to process a reference multi-qubit state by coupling the coded entangled qubit state to the reference multi-qubit state; and
a logic circuit configured to estimate a syndrome value or a parity value of the coded entangled qubit state from measurements on the processed reference multi-qubit state performed by the sequence of quantum gates.
16. The apparatus of claim 15, wherein the logic circuit is configured to:
estimate a respective binary syndrome sub-value or a respective binary parity sub-value from a measurement on individual qubits of the processed reference multi-qubit state; and
the circuit comprises a multi-input XOR gate configured to process said binary sub-values to estimate the syndrome value or the parity value.
17. The apparatus of claim 15, wherein the logic circuit comprises a soft-output detector configured to generate a soft estimate of the syndrome value or of the parity value.
18. The apparatus of claim 1, wherein the coded entangled qubit state is generated using the quantum stabilizer code that is a different LDPC code compared to the LDPC code used for the redundant measurement.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A cup assembly comprising:
a cup having an inner wall formed on an interior of the cup to sandwich a first chamber with an outer periphery of the cup, the inner wall having a first cup cutout defined in a peripheral edge of the inner wall; and
a lid being able to be mounted on top of the cup to close an open end of the cup, the lid having an inner extension extending from a bottom face of the lid to sandwich a second chamber with an outer wall which is extended from a peripheral edge of the lid, the lid having an outlet defined through the lid to communicate with the second chamber, the inner extension having a first lid cutout defined in a peripheral edge of the inner extension to correspond to and selectively align with the first cup cutout of the cup and a second lid cutout defined in the peripheral edge of the inner extension to correspond to the peripheral edge of the inner extension;
wherein a first passage including the first cup cutout of the cup and the first lid cutout of the lid and in communication with the outlet is defined after the lid is mounted on top of the cup;
a second passage including the second lid cutout of the lid is defined after the lid is mounted on top of the cup; and
a liquid cooling compartment including the first chamber and the second chamber is formed after the lid is mounted on top of the cup such that tilting the cup assembly enables the liquid cooling compartment to be filled with liquid contained in the cup when the second passage is in communication with the liquid cooling compartment and the first lid cutout of the lid is in misalignment with the first cup cutout of the cup via rotation of the lid relative to the cup thereby allowing the liquid to flow out of the outlet after communication between the first lid cutout and the first cup cutout is established via the rotation of the lid after temperature of the liquid in the liquid cooling compartment has cooled.
2. The cup assembly as claimed in claim 1, wherein the second lid cutout has a depth sufficient that after the lid is mounted on top of the cup, a portion of the second lid cutout is exposed out of the inner extension to form the second passage.
3. The cup assembly as claimed in claim 2 further comprising a guiding device formed on an outer periphery of the inner wall of the cup and a limiting element formed on the lid to correspond to the guiding device so that when the lid is mounted on top of the cup, the corresponding relationship between the guiding device and the limiting element is able to guide the lid in relation to the cup.
4. The cup assembly as claimed in claim 3, wherein the guiding device comprises a longitudinal slit in the outer periphery of the inner wall and a latitudinal slit bisecting the longitudinal slit, the limiting element is a ball mounted on an outer periphery of the inner extension to correspond to the longitudinal slit and the latitudinal slit such that after the ball is received in the longitudinal slit, the mounting of the lid on the cup is guided and when the ball is received in the latitudinal slit, rotation of the lid relative to the cup is limited due to a length of the latitudinal slit.
5. The cup assembly as claimed in claims 4 further comprising a rotation facilitating device which includes:
multiple teeth formed on a peripheral edge of the outer wall of the lid;
a gear rotatably mounted on the outer periphery of the cup to mate with the teeth of the lid; and
a rack slidably and movably mounted on the cup to mate with the gear to drive the gear to rotate.
6. The cup assembly as claimed in claims 3 further comprising a rotation facilitating device which includes:
multiple teeth formed on a peripheral edge of the outer wall of the lid;
a gear rotatably mounted on the outer periphery of the cup to mate with the teeth of the lid; and
a rack slidably and movably mounted on the cup to mate with the gear to drive the gear to rotate.
7. The cup assembly as claimed in claims 2 further comprising a rotation facilitating device which includes:
multiple teeth formed on a peripheral edge of the outer wall of the lid;
a gear rotatably mounted on the outer periphery of the cup to mate with the teeth of the lid; and
a rack slidably and movably mounted on the cup to mate with the gear to drive the gear to rotate.
8. The cup assembly as claimed in claim 1 further comprising a guiding device formed on an outer periphery of the inner wall, of the cup and a limiting element formed on the lid to correspond to the guiding device so that when the lid is mounted on top of the cup, the corresponding relationship between the guiding device and the limiting element is able to guide the lid in relation to the cup.
9. The cup assembly as claimed in claim 8, wherein the guiding device comprises a longitudinal slit in the outer periphery of the inner wall and a latitudinal slit bisecting the longitudinal slit, the limiting element is a ball mounted on an outer periphery of the inner extension to correspond to the longitudinal slit and the latitudinal slit such that after the ball is received in the longitudinal slit, the mounting of the lid on the cup is guided and when the ball is received in the latitudinal slit, rotation of the lid relative to the cup is limited due to a length of the latitudinal slit.
10. The cup assembly as claimed in claims 9 further comprising a rotation facilitating device which includes:
multiple teeth formed on a peripheral edge of the outer wall of the lid;
a gear rotatably mounted on the outer periphery of the cup to mate with the teeth of the lid; and
a rack slidably and movably mounted on the cup to mate with the gear to drive the gear to rotate.
11. The cup assembly as claimed in claims 9, wherein the cup further has a second cup cutout defined in the peripheral edge of the inner wall to correspond to and selectively align with the second lid cutout of the lid so as to form the second passage.
12. The cup assembly as claimed in claims 8 further comprising a rotation facilitating device which includes:
multiple teeth formed on a peripheral edge of the outer wall of the lid;
a gear rotatably mounted on the outer periphery of the cup to mate with the teeth of the lid; and
a rack slidably and movably mounted on the cup to mate with the gear to drive the gear to rotate.
13. The cup assembly as claimed in claims 8, wherein the cup further has a second cup cutout defined in the peripheral edge of the inner wall to correspond to and selectively align with the second lid cutout of the lid so as to form the second passage.
14. The cup assembly as claimed in claims 1 further comprising a rotation facilitating device which includes:
multiple teeth formed on a peripheral edge of the outer wall of the lid;
a gear rotatably mounted on the outer periphery of the cup to mate with the teeth of the lid; and
a rack slidably and movably mounted on the cup to mate with the gear to drive the gear to rotate.
15. The cup assembly as claimed in claim 14, wherein the cup further has a second cup cutout defined in the peripheral edge of the inner wall to correspond to and selectively align with the second lid cutout of the lid so as to form the second passage.
16. The cup assembly as claimed in claims 1, wherein the cup further has a second cup cutout defined in the peripheral edge of the inner wall to correspond to and selectively align with the second lid cutout of the lid so as to form the second passage.