Entanglement Generation

Code for Barrett-Kok entanglement Generation protocol

This module defines code to support entanglement generation between single-atom memories on distant nodes. Also defined is the message type used by this implementation. Entanglement generation is asymmetric:

  • EntanglementGenerationA should be used on the QuantumRouter (with one node set as the primary) and should be started via the “start” method

  • EntanglementGeneraitonB should be used on the BSMNode and does not need to be started

class src.entanglement_management.generation.EntanglementGenerationA(own: Node, name: str, middle: str, other: str, memory: Memory)

Entanglement generation protocol for quantum router.

The EntanglementGenerationA protocol should be instantiated on a quantum router node. Instances will communicate with each other (and with the B instance on a BSM node) to generate entanglement.

own

node that protocol instance is attached to.

Type:

QuantumRouter

name

label for protocol instance.

Type:

str

middle

name of BSM measurement node where emitted photons should be directed.

Type:

str

remote_node_name

name of distant QuantumRouter node, containing a memory to be entangled with local memory.

Type:

str

memory

quantum memory object to attempt entanglement for.

Type:

Memory

emit_event() → None

Method to set up memory and emit photons.

If the protocol is in round 1, the memory will be first set to the |+> state. Otherwise, it will apply an x_gate to the memory. Regardless of the round, the memory excite method will be invoked.

Side Effects:

May change state of attached memory. May cause attached memory to emit photon.

is_ready() → bool

Method to check if protocol is ready to start (abstract).

Returns:

if protocol is ready or not.

Return type:

bool

memory_expire(memory: Memory) → None

Method to receive expired memories.

received_message(src: str, msg: EntanglementGenerationMessage) → None

Method to receive messages.

This method receives messages from other entanglement generation protocols. Depending on the message, different actions may be taken by the protocol.

Parameters:
Side Effects:

May schedule various internal and hardware events.

set_others(protocol: str, node: str, memories: List[str]) → None

Method to set other entanglement protocol instance.

Parameters:

  • protocol (str) – other protocol name.

  • node (str) – other node name.

  • memories (List[str]) – the list of memory names used on other node.

start() → None

Method to start entanglement generation protocol.

Will start negotiations with other protocol (if primary).

Side Effects:

Will send message through attached node.

update_memory()

Method to handle necessary memory operations.

Called on both nodes. Will check the state of the memory and protocol.

Returns:

if current round was successfull.

Return type:

bool

Side Effects:

May change state of attached memory. May update memory state in the attached node’s resource manager.

class src.entanglement_management.generation.EntanglementGenerationB(own: BSMNode, name: str, others: List[str])

Entanglement generation protocol for BSM node.

The EntanglementGenerationB protocol should be instantiated on a BSM node. Instances will communicate with the A instance on neighboring quantum router nodes to generate entanglement.

own

node that protocol instance is attached to.

Type:

BSMNode

name

label for protocol instance.

Type:

str

others

list of neighboring quantum router nodes

Type:

List[str]

bsm_update(bsm: SingleAtomBSM, info: Dict[str, Any])

Method to receive detection events from BSM on node.

Parameters:

  • bsm (SingleAtomBSM) – bsm object calling method.

  • info (Dict[str, any]) – information passed from bsm.

is_ready() → bool

Method to check if protocol is ready to start (abstract).

Returns:

if protocol is ready or not.

Return type:

bool

memory_expire(memory: Memory) → None

Method to receive a memory expiration event (abstract).

received_message(src: str, msg: EntanglementGenerationMessage)

Receive classical message from another node.

set_others(protocol: str, node: str, memories: List[str]) → None

Method to set other entanglement protocol instance.

Parameters:

  • remote_protocol (str) – other protocol name.

  • remote_node (str) – other node name.

  • memories (List[str]) – the list of memory names used on other node.

start() → None

Method to start entanglement protocol process (abstract).

class src.entanglement_management.generation.EntanglementGenerationMessage(msg_type: GenerationMsgType, receiver: str, **kwargs)

Message used by entanglement generation protocols.

This message contains all information passed between generation protocol instances. Messages of different types contain different information.

msg_type

defines the message type.

Type:

GenerationMsgType

receiver

name of destination protocol instance.

Type:

str

qc_delay

quantum channel delay to BSM node (if msg_type == NEGOTIATE).

Type:

int

frequency

frequency with which local memory can be excited (if msg_type == NEGOTIATE).

Type:

float

emit_time

time to emit photon for measurement (if msg_type == NEGOTIATE_ACK).

Type:

int

res

detector number at BSM node (if msg_type == MEAS_RES).

Type:

int

time

detection time at BSM node (if msg_type == MEAS_RES).

Type:

int

resolution

time resolution of BSM detectors (if msg_type == MEAS_RES).

Type:

int

class src.entanglement_management.generation.GenerationMsgType(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)

Defines possible message types for entanglement generation.